target/mips/rel6_translate: Change license to GNU LGPL v2.1 (or later)
[qemu/ar7.git] / migration / migration.c
blob8ca034136bc11cedd8132e5fb9138f50f5442e94
1 /*
2 * QEMU live migration
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
12 * Contributions after 2012-01-13 are licensed under the terms of the
13 * GNU GPL, version 2 or (at your option) any later version.
16 #include "qemu/osdep.h"
17 #include "qemu/cutils.h"
18 #include "qemu/error-report.h"
19 #include "qemu/main-loop.h"
20 #include "migration/blocker.h"
21 #include "exec.h"
22 #include "fd.h"
23 #include "socket.h"
24 #include "sysemu/runstate.h"
25 #include "sysemu/sysemu.h"
26 #include "sysemu/cpu-throttle.h"
27 #include "rdma.h"
28 #include "ram.h"
29 #include "migration/global_state.h"
30 #include "migration/misc.h"
31 #include "migration.h"
32 #include "savevm.h"
33 #include "qemu-file-channel.h"
34 #include "qemu-file.h"
35 #include "migration/vmstate.h"
36 #include "block/block.h"
37 #include "qapi/error.h"
38 #include "qapi/clone-visitor.h"
39 #include "qapi/qapi-visit-migration.h"
40 #include "qapi/qapi-visit-sockets.h"
41 #include "qapi/qapi-commands-migration.h"
42 #include "qapi/qapi-events-migration.h"
43 #include "qapi/qmp/qerror.h"
44 #include "qapi/qmp/qnull.h"
45 #include "qemu/rcu.h"
46 #include "block.h"
47 #include "postcopy-ram.h"
48 #include "qemu/thread.h"
49 #include "trace.h"
50 #include "exec/target_page.h"
51 #include "io/channel-buffer.h"
52 #include "migration/colo.h"
53 #include "hw/boards.h"
54 #include "hw/qdev-properties.h"
55 #include "hw/qdev-properties-system.h"
56 #include "monitor/monitor.h"
57 #include "net/announce.h"
58 #include "qemu/queue.h"
59 #include "multifd.h"
60 #include "qemu/yank.h"
61 #include "sysemu/cpus.h"
63 #ifdef CONFIG_VFIO
64 #include "hw/vfio/vfio-common.h"
65 #endif
67 #define MAX_THROTTLE (128 << 20) /* Migration transfer speed throttling */
69 /* Amount of time to allocate to each "chunk" of bandwidth-throttled
70 * data. */
71 #define BUFFER_DELAY 100
72 #define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
74 /* Time in milliseconds we are allowed to stop the source,
75 * for sending the last part */
76 #define DEFAULT_MIGRATE_SET_DOWNTIME 300
78 /* Maximum migrate downtime set to 2000 seconds */
79 #define MAX_MIGRATE_DOWNTIME_SECONDS 2000
80 #define MAX_MIGRATE_DOWNTIME (MAX_MIGRATE_DOWNTIME_SECONDS * 1000)
82 /* Default compression thread count */
83 #define DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT 8
84 /* Default decompression thread count, usually decompression is at
85 * least 4 times as fast as compression.*/
86 #define DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT 2
87 /*0: means nocompress, 1: best speed, ... 9: best compress ratio */
88 #define DEFAULT_MIGRATE_COMPRESS_LEVEL 1
89 /* Define default autoconverge cpu throttle migration parameters */
90 #define DEFAULT_MIGRATE_THROTTLE_TRIGGER_THRESHOLD 50
91 #define DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL 20
92 #define DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT 10
93 #define DEFAULT_MIGRATE_MAX_CPU_THROTTLE 99
95 /* Migration XBZRLE default cache size */
96 #define DEFAULT_MIGRATE_XBZRLE_CACHE_SIZE (64 * 1024 * 1024)
98 /* The delay time (in ms) between two COLO checkpoints */
99 #define DEFAULT_MIGRATE_X_CHECKPOINT_DELAY (200 * 100)
100 #define DEFAULT_MIGRATE_MULTIFD_CHANNELS 2
101 #define DEFAULT_MIGRATE_MULTIFD_COMPRESSION MULTIFD_COMPRESSION_NONE
102 /* 0: means nocompress, 1: best speed, ... 9: best compress ratio */
103 #define DEFAULT_MIGRATE_MULTIFD_ZLIB_LEVEL 1
104 /* 0: means nocompress, 1: best speed, ... 20: best compress ratio */
105 #define DEFAULT_MIGRATE_MULTIFD_ZSTD_LEVEL 1
107 /* Background transfer rate for postcopy, 0 means unlimited, note
108 * that page requests can still exceed this limit.
110 #define DEFAULT_MIGRATE_MAX_POSTCOPY_BANDWIDTH 0
113 * Parameters for self_announce_delay giving a stream of RARP/ARP
114 * packets after migration.
116 #define DEFAULT_MIGRATE_ANNOUNCE_INITIAL 50
117 #define DEFAULT_MIGRATE_ANNOUNCE_MAX 550
118 #define DEFAULT_MIGRATE_ANNOUNCE_ROUNDS 5
119 #define DEFAULT_MIGRATE_ANNOUNCE_STEP 100
121 static NotifierList migration_state_notifiers =
122 NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
124 /* Messages sent on the return path from destination to source */
125 enum mig_rp_message_type {
126 MIG_RP_MSG_INVALID = 0, /* Must be 0 */
127 MIG_RP_MSG_SHUT, /* sibling will not send any more RP messages */
128 MIG_RP_MSG_PONG, /* Response to a PING; data (seq: be32 ) */
130 MIG_RP_MSG_REQ_PAGES_ID, /* data (start: be64, len: be32, id: string) */
131 MIG_RP_MSG_REQ_PAGES, /* data (start: be64, len: be32) */
132 MIG_RP_MSG_RECV_BITMAP, /* send recved_bitmap back to source */
133 MIG_RP_MSG_RESUME_ACK, /* tell source that we are ready to resume */
135 MIG_RP_MSG_MAX
138 /* Migration capabilities set */
139 struct MigrateCapsSet {
140 int size; /* Capability set size */
141 MigrationCapability caps[]; /* Variadic array of capabilities */
143 typedef struct MigrateCapsSet MigrateCapsSet;
145 /* Define and initialize MigrateCapsSet */
146 #define INITIALIZE_MIGRATE_CAPS_SET(_name, ...) \
147 MigrateCapsSet _name = { \
148 .size = sizeof((int []) { __VA_ARGS__ }) / sizeof(int), \
149 .caps = { __VA_ARGS__ } \
152 /* Background-snapshot compatibility check list */
153 static const
154 INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot,
155 MIGRATION_CAPABILITY_POSTCOPY_RAM,
156 MIGRATION_CAPABILITY_DIRTY_BITMAPS,
157 MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME,
158 MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE,
159 MIGRATION_CAPABILITY_RETURN_PATH,
160 MIGRATION_CAPABILITY_MULTIFD,
161 MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER,
162 MIGRATION_CAPABILITY_AUTO_CONVERGE,
163 MIGRATION_CAPABILITY_RELEASE_RAM,
164 MIGRATION_CAPABILITY_RDMA_PIN_ALL,
165 MIGRATION_CAPABILITY_COMPRESS,
166 MIGRATION_CAPABILITY_XBZRLE,
167 MIGRATION_CAPABILITY_X_COLO,
168 MIGRATION_CAPABILITY_VALIDATE_UUID);
170 /* When we add fault tolerance, we could have several
171 migrations at once. For now we don't need to add
172 dynamic creation of migration */
174 static MigrationState *current_migration;
175 static MigrationIncomingState *current_incoming;
177 static GSList *migration_blockers;
179 static bool migration_object_check(MigrationState *ms, Error **errp);
180 static int migration_maybe_pause(MigrationState *s,
181 int *current_active_state,
182 int new_state);
183 static void migrate_fd_cancel(MigrationState *s);
185 static gint page_request_addr_cmp(gconstpointer ap, gconstpointer bp)
187 uintptr_t a = (uintptr_t) ap, b = (uintptr_t) bp;
189 return (a > b) - (a < b);
192 void migration_object_init(void)
194 Error *err = NULL;
196 /* This can only be called once. */
197 assert(!current_migration);
198 current_migration = MIGRATION_OBJ(object_new(TYPE_MIGRATION));
201 * Init the migrate incoming object as well no matter whether
202 * we'll use it or not.
204 assert(!current_incoming);
205 current_incoming = g_new0(MigrationIncomingState, 1);
206 current_incoming->state = MIGRATION_STATUS_NONE;
207 current_incoming->postcopy_remote_fds =
208 g_array_new(FALSE, TRUE, sizeof(struct PostCopyFD));
209 qemu_mutex_init(&current_incoming->rp_mutex);
210 qemu_event_init(&current_incoming->main_thread_load_event, false);
211 qemu_sem_init(&current_incoming->postcopy_pause_sem_dst, 0);
212 qemu_sem_init(&current_incoming->postcopy_pause_sem_fault, 0);
213 qemu_mutex_init(&current_incoming->page_request_mutex);
214 current_incoming->page_requested = g_tree_new(page_request_addr_cmp);
216 if (!migration_object_check(current_migration, &err)) {
217 error_report_err(err);
218 exit(1);
221 blk_mig_init();
222 ram_mig_init();
223 dirty_bitmap_mig_init();
226 void migration_shutdown(void)
229 * Cancel the current migration - that will (eventually)
230 * stop the migration using this structure
232 migrate_fd_cancel(current_migration);
233 object_unref(OBJECT(current_migration));
236 * Cancel outgoing migration of dirty bitmaps. It should
237 * at least unref used block nodes.
239 dirty_bitmap_mig_cancel_outgoing();
242 * Cancel incoming migration of dirty bitmaps. Dirty bitmaps
243 * are non-critical data, and their loss never considered as
244 * something serious.
246 dirty_bitmap_mig_cancel_incoming();
249 /* For outgoing */
250 MigrationState *migrate_get_current(void)
252 /* This can only be called after the object created. */
253 assert(current_migration);
254 return current_migration;
257 MigrationIncomingState *migration_incoming_get_current(void)
259 assert(current_incoming);
260 return current_incoming;
263 void migration_incoming_state_destroy(void)
265 struct MigrationIncomingState *mis = migration_incoming_get_current();
267 if (mis->to_src_file) {
268 /* Tell source that we are done */
269 migrate_send_rp_shut(mis, qemu_file_get_error(mis->from_src_file) != 0);
270 qemu_fclose(mis->to_src_file);
271 mis->to_src_file = NULL;
274 if (mis->from_src_file) {
275 qemu_fclose(mis->from_src_file);
276 mis->from_src_file = NULL;
278 if (mis->postcopy_remote_fds) {
279 g_array_free(mis->postcopy_remote_fds, TRUE);
280 mis->postcopy_remote_fds = NULL;
283 qemu_event_reset(&mis->main_thread_load_event);
285 if (mis->page_requested) {
286 g_tree_destroy(mis->page_requested);
287 mis->page_requested = NULL;
290 if (mis->socket_address_list) {
291 qapi_free_SocketAddressList(mis->socket_address_list);
292 mis->socket_address_list = NULL;
295 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
298 static void migrate_generate_event(int new_state)
300 if (migrate_use_events()) {
301 qapi_event_send_migration(new_state);
305 static bool migrate_late_block_activate(void)
307 MigrationState *s;
309 s = migrate_get_current();
311 return s->enabled_capabilities[
312 MIGRATION_CAPABILITY_LATE_BLOCK_ACTIVATE];
316 * Send a message on the return channel back to the source
317 * of the migration.
319 static int migrate_send_rp_message(MigrationIncomingState *mis,
320 enum mig_rp_message_type message_type,
321 uint16_t len, void *data)
323 int ret = 0;
325 trace_migrate_send_rp_message((int)message_type, len);
326 QEMU_LOCK_GUARD(&mis->rp_mutex);
329 * It's possible that the file handle got lost due to network
330 * failures.
332 if (!mis->to_src_file) {
333 ret = -EIO;
334 return ret;
337 qemu_put_be16(mis->to_src_file, (unsigned int)message_type);
338 qemu_put_be16(mis->to_src_file, len);
339 qemu_put_buffer(mis->to_src_file, data, len);
340 qemu_fflush(mis->to_src_file);
342 /* It's possible that qemu file got error during sending */
343 ret = qemu_file_get_error(mis->to_src_file);
345 return ret;
348 /* Request one page from the source VM at the given start address.
349 * rb: the RAMBlock to request the page in
350 * Start: Address offset within the RB
351 * Len: Length in bytes required - must be a multiple of pagesize
353 int migrate_send_rp_message_req_pages(MigrationIncomingState *mis,
354 RAMBlock *rb, ram_addr_t start)
356 uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */
357 size_t msglen = 12; /* start + len */
358 size_t len = qemu_ram_pagesize(rb);
359 enum mig_rp_message_type msg_type;
360 const char *rbname;
361 int rbname_len;
363 *(uint64_t *)bufc = cpu_to_be64((uint64_t)start);
364 *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len);
367 * We maintain the last ramblock that we requested for page. Note that we
368 * don't need locking because this function will only be called within the
369 * postcopy ram fault thread.
371 if (rb != mis->last_rb) {
372 mis->last_rb = rb;
374 rbname = qemu_ram_get_idstr(rb);
375 rbname_len = strlen(rbname);
377 assert(rbname_len < 256);
379 bufc[msglen++] = rbname_len;
380 memcpy(bufc + msglen, rbname, rbname_len);
381 msglen += rbname_len;
382 msg_type = MIG_RP_MSG_REQ_PAGES_ID;
383 } else {
384 msg_type = MIG_RP_MSG_REQ_PAGES;
387 return migrate_send_rp_message(mis, msg_type, msglen, bufc);
390 int migrate_send_rp_req_pages(MigrationIncomingState *mis,
391 RAMBlock *rb, ram_addr_t start, uint64_t haddr)
393 void *aligned = (void *)(uintptr_t)(haddr & (-qemu_ram_pagesize(rb)));
394 bool received = false;
396 WITH_QEMU_LOCK_GUARD(&mis->page_request_mutex) {
397 received = ramblock_recv_bitmap_test_byte_offset(rb, start);
398 if (!received && !g_tree_lookup(mis->page_requested, aligned)) {
400 * The page has not been received, and it's not yet in the page
401 * request list. Queue it. Set the value of element to 1, so that
402 * things like g_tree_lookup() will return TRUE (1) when found.
404 g_tree_insert(mis->page_requested, aligned, (gpointer)1);
405 mis->page_requested_count++;
406 trace_postcopy_page_req_add(aligned, mis->page_requested_count);
411 * If the page is there, skip sending the message. We don't even need the
412 * lock because as long as the page arrived, it'll be there forever.
414 if (received) {
415 return 0;
418 return migrate_send_rp_message_req_pages(mis, rb, start);
421 static bool migration_colo_enabled;
422 bool migration_incoming_colo_enabled(void)
424 return migration_colo_enabled;
427 void migration_incoming_disable_colo(void)
429 ram_block_discard_disable(false);
430 migration_colo_enabled = false;
433 int migration_incoming_enable_colo(void)
435 if (ram_block_discard_disable(true)) {
436 error_report("COLO: cannot disable RAM discard");
437 return -EBUSY;
439 migration_colo_enabled = true;
440 return 0;
443 void migrate_add_address(SocketAddress *address)
445 MigrationIncomingState *mis = migration_incoming_get_current();
447 QAPI_LIST_PREPEND(mis->socket_address_list,
448 QAPI_CLONE(SocketAddress, address));
451 static void qemu_start_incoming_migration(const char *uri, Error **errp)
453 const char *p = NULL;
455 if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
456 return;
459 qapi_event_send_migration(MIGRATION_STATUS_SETUP);
460 if (strstart(uri, "tcp:", &p) ||
461 strstart(uri, "unix:", NULL) ||
462 strstart(uri, "vsock:", NULL)) {
463 socket_start_incoming_migration(p ? p : uri, errp);
464 #ifdef CONFIG_RDMA
465 } else if (strstart(uri, "rdma:", &p)) {
466 rdma_start_incoming_migration(p, errp);
467 #endif
468 } else if (strstart(uri, "exec:", &p)) {
469 exec_start_incoming_migration(p, errp);
470 } else if (strstart(uri, "fd:", &p)) {
471 fd_start_incoming_migration(p, errp);
472 } else {
473 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
474 error_setg(errp, "unknown migration protocol: %s", uri);
478 static void process_incoming_migration_bh(void *opaque)
480 Error *local_err = NULL;
481 MigrationIncomingState *mis = opaque;
483 /* If capability late_block_activate is set:
484 * Only fire up the block code now if we're going to restart the
485 * VM, else 'cont' will do it.
486 * This causes file locking to happen; so we don't want it to happen
487 * unless we really are starting the VM.
489 if (!migrate_late_block_activate() ||
490 (autostart && (!global_state_received() ||
491 global_state_get_runstate() == RUN_STATE_RUNNING))) {
492 /* Make sure all file formats flush their mutable metadata.
493 * If we get an error here, just don't restart the VM yet. */
494 bdrv_invalidate_cache_all(&local_err);
495 if (local_err) {
496 error_report_err(local_err);
497 local_err = NULL;
498 autostart = false;
503 * This must happen after all error conditions are dealt with and
504 * we're sure the VM is going to be running on this host.
506 qemu_announce_self(&mis->announce_timer, migrate_announce_params());
508 if (multifd_load_cleanup(&local_err) != 0) {
509 error_report_err(local_err);
510 autostart = false;
512 /* If global state section was not received or we are in running
513 state, we need to obey autostart. Any other state is set with
514 runstate_set. */
516 dirty_bitmap_mig_before_vm_start();
518 if (!global_state_received() ||
519 global_state_get_runstate() == RUN_STATE_RUNNING) {
520 if (autostart) {
521 vm_start();
522 } else {
523 runstate_set(RUN_STATE_PAUSED);
525 } else if (migration_incoming_colo_enabled()) {
526 migration_incoming_disable_colo();
527 vm_start();
528 } else {
529 runstate_set(global_state_get_runstate());
532 * This must happen after any state changes since as soon as an external
533 * observer sees this event they might start to prod at the VM assuming
534 * it's ready to use.
536 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
537 MIGRATION_STATUS_COMPLETED);
538 qemu_bh_delete(mis->bh);
539 migration_incoming_state_destroy();
542 static void process_incoming_migration_co(void *opaque)
544 MigrationIncomingState *mis = migration_incoming_get_current();
545 PostcopyState ps;
546 int ret;
547 Error *local_err = NULL;
549 assert(mis->from_src_file);
550 mis->migration_incoming_co = qemu_coroutine_self();
551 mis->largest_page_size = qemu_ram_pagesize_largest();
552 postcopy_state_set(POSTCOPY_INCOMING_NONE);
553 migrate_set_state(&mis->state, MIGRATION_STATUS_NONE,
554 MIGRATION_STATUS_ACTIVE);
555 ret = qemu_loadvm_state(mis->from_src_file);
557 ps = postcopy_state_get();
558 trace_process_incoming_migration_co_end(ret, ps);
559 if (ps != POSTCOPY_INCOMING_NONE) {
560 if (ps == POSTCOPY_INCOMING_ADVISE) {
562 * Where a migration had postcopy enabled (and thus went to advise)
563 * but managed to complete within the precopy period, we can use
564 * the normal exit.
566 postcopy_ram_incoming_cleanup(mis);
567 } else if (ret >= 0) {
569 * Postcopy was started, cleanup should happen at the end of the
570 * postcopy thread.
572 trace_process_incoming_migration_co_postcopy_end_main();
573 return;
575 /* Else if something went wrong then just fall out of the normal exit */
578 /* we get COLO info, and know if we are in COLO mode */
579 if (!ret && migration_incoming_colo_enabled()) {
580 /* Make sure all file formats flush their mutable metadata */
581 bdrv_invalidate_cache_all(&local_err);
582 if (local_err) {
583 error_report_err(local_err);
584 goto fail;
587 qemu_thread_create(&mis->colo_incoming_thread, "COLO incoming",
588 colo_process_incoming_thread, mis, QEMU_THREAD_JOINABLE);
589 mis->have_colo_incoming_thread = true;
590 qemu_coroutine_yield();
592 /* Wait checkpoint incoming thread exit before free resource */
593 qemu_thread_join(&mis->colo_incoming_thread);
594 /* We hold the global iothread lock, so it is safe here */
595 colo_release_ram_cache();
598 if (ret < 0) {
599 error_report("load of migration failed: %s", strerror(-ret));
600 goto fail;
602 mis->bh = qemu_bh_new(process_incoming_migration_bh, mis);
603 qemu_bh_schedule(mis->bh);
604 mis->migration_incoming_co = NULL;
605 return;
606 fail:
607 local_err = NULL;
608 migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
609 MIGRATION_STATUS_FAILED);
610 qemu_fclose(mis->from_src_file);
611 if (multifd_load_cleanup(&local_err) != 0) {
612 error_report_err(local_err);
614 exit(EXIT_FAILURE);
618 * @migration_incoming_setup: Setup incoming migration
620 * Returns 0 for no error or 1 for error
622 * @f: file for main migration channel
623 * @errp: where to put errors
625 static int migration_incoming_setup(QEMUFile *f, Error **errp)
627 MigrationIncomingState *mis = migration_incoming_get_current();
628 Error *local_err = NULL;
630 if (multifd_load_setup(&local_err) != 0) {
631 /* We haven't been able to create multifd threads
632 nothing better to do */
633 error_report_err(local_err);
634 exit(EXIT_FAILURE);
637 if (!mis->from_src_file) {
638 mis->from_src_file = f;
640 qemu_file_set_blocking(f, false);
641 return 0;
644 void migration_incoming_process(void)
646 Coroutine *co = qemu_coroutine_create(process_incoming_migration_co, NULL);
647 qemu_coroutine_enter(co);
650 /* Returns true if recovered from a paused migration, otherwise false */
651 static bool postcopy_try_recover(QEMUFile *f)
653 MigrationIncomingState *mis = migration_incoming_get_current();
655 if (mis->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
656 /* Resumed from a paused postcopy migration */
658 mis->from_src_file = f;
659 /* Postcopy has standalone thread to do vm load */
660 qemu_file_set_blocking(f, true);
662 /* Re-configure the return path */
663 mis->to_src_file = qemu_file_get_return_path(f);
665 migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
666 MIGRATION_STATUS_POSTCOPY_RECOVER);
669 * Here, we only wake up the main loading thread (while the
670 * fault thread will still be waiting), so that we can receive
671 * commands from source now, and answer it if needed. The
672 * fault thread will be woken up afterwards until we are sure
673 * that source is ready to reply to page requests.
675 qemu_sem_post(&mis->postcopy_pause_sem_dst);
676 return true;
679 return false;
682 void migration_fd_process_incoming(QEMUFile *f, Error **errp)
684 Error *local_err = NULL;
686 if (postcopy_try_recover(f)) {
687 return;
690 if (migration_incoming_setup(f, &local_err)) {
691 error_propagate(errp, local_err);
692 return;
694 migration_incoming_process();
697 void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
699 MigrationIncomingState *mis = migration_incoming_get_current();
700 Error *local_err = NULL;
701 bool start_migration;
703 if (!mis->from_src_file) {
704 /* The first connection (multifd may have multiple) */
705 QEMUFile *f = qemu_fopen_channel_input(ioc);
707 /* If it's a recovery, we're done */
708 if (postcopy_try_recover(f)) {
709 return;
712 if (migration_incoming_setup(f, &local_err)) {
713 error_propagate(errp, local_err);
714 return;
718 * Common migration only needs one channel, so we can start
719 * right now. Multifd needs more than one channel, we wait.
721 start_migration = !migrate_use_multifd();
722 } else {
723 /* Multiple connections */
724 assert(migrate_use_multifd());
725 start_migration = multifd_recv_new_channel(ioc, &local_err);
726 if (local_err) {
727 error_propagate(errp, local_err);
728 return;
732 if (start_migration) {
733 migration_incoming_process();
738 * @migration_has_all_channels: We have received all channels that we need
740 * Returns true when we have got connections to all the channels that
741 * we need for migration.
743 bool migration_has_all_channels(void)
745 MigrationIncomingState *mis = migration_incoming_get_current();
746 bool all_channels;
748 all_channels = multifd_recv_all_channels_created();
750 return all_channels && mis->from_src_file != NULL;
754 * Send a 'SHUT' message on the return channel with the given value
755 * to indicate that we've finished with the RP. Non-0 value indicates
756 * error.
758 void migrate_send_rp_shut(MigrationIncomingState *mis,
759 uint32_t value)
761 uint32_t buf;
763 buf = cpu_to_be32(value);
764 migrate_send_rp_message(mis, MIG_RP_MSG_SHUT, sizeof(buf), &buf);
768 * Send a 'PONG' message on the return channel with the given value
769 * (normally in response to a 'PING')
771 void migrate_send_rp_pong(MigrationIncomingState *mis,
772 uint32_t value)
774 uint32_t buf;
776 buf = cpu_to_be32(value);
777 migrate_send_rp_message(mis, MIG_RP_MSG_PONG, sizeof(buf), &buf);
780 void migrate_send_rp_recv_bitmap(MigrationIncomingState *mis,
781 char *block_name)
783 char buf[512];
784 int len;
785 int64_t res;
788 * First, we send the header part. It contains only the len of
789 * idstr, and the idstr itself.
791 len = strlen(block_name);
792 buf[0] = len;
793 memcpy(buf + 1, block_name, len);
795 if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {
796 error_report("%s: MSG_RP_RECV_BITMAP only used for recovery",
797 __func__);
798 return;
801 migrate_send_rp_message(mis, MIG_RP_MSG_RECV_BITMAP, len + 1, buf);
804 * Next, we dump the received bitmap to the stream.
806 * TODO: currently we are safe since we are the only one that is
807 * using the to_src_file handle (fault thread is still paused),
808 * and it's ok even not taking the mutex. However the best way is
809 * to take the lock before sending the message header, and release
810 * the lock after sending the bitmap.
812 qemu_mutex_lock(&mis->rp_mutex);
813 res = ramblock_recv_bitmap_send(mis->to_src_file, block_name);
814 qemu_mutex_unlock(&mis->rp_mutex);
816 trace_migrate_send_rp_recv_bitmap(block_name, res);
819 void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value)
821 uint32_t buf;
823 buf = cpu_to_be32(value);
824 migrate_send_rp_message(mis, MIG_RP_MSG_RESUME_ACK, sizeof(buf), &buf);
827 MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
829 MigrationCapabilityStatusList *head = NULL, **tail = &head;
830 MigrationCapabilityStatus *caps;
831 MigrationState *s = migrate_get_current();
832 int i;
834 for (i = 0; i < MIGRATION_CAPABILITY__MAX; i++) {
835 #ifndef CONFIG_LIVE_BLOCK_MIGRATION
836 if (i == MIGRATION_CAPABILITY_BLOCK) {
837 continue;
839 #endif
840 caps = g_malloc0(sizeof(*caps));
841 caps->capability = i;
842 caps->state = s->enabled_capabilities[i];
843 QAPI_LIST_APPEND(tail, caps);
846 return head;
849 MigrationParameters *qmp_query_migrate_parameters(Error **errp)
851 MigrationParameters *params;
852 MigrationState *s = migrate_get_current();
854 /* TODO use QAPI_CLONE() instead of duplicating it inline */
855 params = g_malloc0(sizeof(*params));
856 params->has_compress_level = true;
857 params->compress_level = s->parameters.compress_level;
858 params->has_compress_threads = true;
859 params->compress_threads = s->parameters.compress_threads;
860 params->has_compress_wait_thread = true;
861 params->compress_wait_thread = s->parameters.compress_wait_thread;
862 params->has_decompress_threads = true;
863 params->decompress_threads = s->parameters.decompress_threads;
864 params->has_throttle_trigger_threshold = true;
865 params->throttle_trigger_threshold = s->parameters.throttle_trigger_threshold;
866 params->has_cpu_throttle_initial = true;
867 params->cpu_throttle_initial = s->parameters.cpu_throttle_initial;
868 params->has_cpu_throttle_increment = true;
869 params->cpu_throttle_increment = s->parameters.cpu_throttle_increment;
870 params->has_cpu_throttle_tailslow = true;
871 params->cpu_throttle_tailslow = s->parameters.cpu_throttle_tailslow;
872 params->has_tls_creds = true;
873 params->tls_creds = g_strdup(s->parameters.tls_creds);
874 params->has_tls_hostname = true;
875 params->tls_hostname = g_strdup(s->parameters.tls_hostname);
876 params->has_tls_authz = true;
877 params->tls_authz = g_strdup(s->parameters.tls_authz ?
878 s->parameters.tls_authz : "");
879 params->has_max_bandwidth = true;
880 params->max_bandwidth = s->parameters.max_bandwidth;
881 params->has_downtime_limit = true;
882 params->downtime_limit = s->parameters.downtime_limit;
883 params->has_x_checkpoint_delay = true;
884 params->x_checkpoint_delay = s->parameters.x_checkpoint_delay;
885 params->has_block_incremental = true;
886 params->block_incremental = s->parameters.block_incremental;
887 params->has_multifd_channels = true;
888 params->multifd_channels = s->parameters.multifd_channels;
889 params->has_multifd_compression = true;
890 params->multifd_compression = s->parameters.multifd_compression;
891 params->has_multifd_zlib_level = true;
892 params->multifd_zlib_level = s->parameters.multifd_zlib_level;
893 params->has_multifd_zstd_level = true;
894 params->multifd_zstd_level = s->parameters.multifd_zstd_level;
895 params->has_xbzrle_cache_size = true;
896 params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
897 params->has_max_postcopy_bandwidth = true;
898 params->max_postcopy_bandwidth = s->parameters.max_postcopy_bandwidth;
899 params->has_max_cpu_throttle = true;
900 params->max_cpu_throttle = s->parameters.max_cpu_throttle;
901 params->has_announce_initial = true;
902 params->announce_initial = s->parameters.announce_initial;
903 params->has_announce_max = true;
904 params->announce_max = s->parameters.announce_max;
905 params->has_announce_rounds = true;
906 params->announce_rounds = s->parameters.announce_rounds;
907 params->has_announce_step = true;
908 params->announce_step = s->parameters.announce_step;
910 if (s->parameters.has_block_bitmap_mapping) {
911 params->has_block_bitmap_mapping = true;
912 params->block_bitmap_mapping =
913 QAPI_CLONE(BitmapMigrationNodeAliasList,
914 s->parameters.block_bitmap_mapping);
917 return params;
920 AnnounceParameters *migrate_announce_params(void)
922 static AnnounceParameters ap;
924 MigrationState *s = migrate_get_current();
926 ap.initial = s->parameters.announce_initial;
927 ap.max = s->parameters.announce_max;
928 ap.rounds = s->parameters.announce_rounds;
929 ap.step = s->parameters.announce_step;
931 return &ap;
935 * Return true if we're already in the middle of a migration
936 * (i.e. any of the active or setup states)
938 bool migration_is_setup_or_active(int state)
940 switch (state) {
941 case MIGRATION_STATUS_ACTIVE:
942 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
943 case MIGRATION_STATUS_POSTCOPY_PAUSED:
944 case MIGRATION_STATUS_POSTCOPY_RECOVER:
945 case MIGRATION_STATUS_SETUP:
946 case MIGRATION_STATUS_PRE_SWITCHOVER:
947 case MIGRATION_STATUS_DEVICE:
948 case MIGRATION_STATUS_WAIT_UNPLUG:
949 case MIGRATION_STATUS_COLO:
950 return true;
952 default:
953 return false;
958 bool migration_is_running(int state)
960 switch (state) {
961 case MIGRATION_STATUS_ACTIVE:
962 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
963 case MIGRATION_STATUS_POSTCOPY_PAUSED:
964 case MIGRATION_STATUS_POSTCOPY_RECOVER:
965 case MIGRATION_STATUS_SETUP:
966 case MIGRATION_STATUS_PRE_SWITCHOVER:
967 case MIGRATION_STATUS_DEVICE:
968 case MIGRATION_STATUS_WAIT_UNPLUG:
969 case MIGRATION_STATUS_CANCELLING:
970 return true;
972 default:
973 return false;
978 static void populate_time_info(MigrationInfo *info, MigrationState *s)
980 info->has_status = true;
981 info->has_setup_time = true;
982 info->setup_time = s->setup_time;
983 if (s->state == MIGRATION_STATUS_COMPLETED) {
984 info->has_total_time = true;
985 info->total_time = s->total_time;
986 info->has_downtime = true;
987 info->downtime = s->downtime;
988 } else {
989 info->has_total_time = true;
990 info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) -
991 s->start_time;
992 info->has_expected_downtime = true;
993 info->expected_downtime = s->expected_downtime;
997 static void populate_ram_info(MigrationInfo *info, MigrationState *s)
999 info->has_ram = true;
1000 info->ram = g_malloc0(sizeof(*info->ram));
1001 info->ram->transferred = ram_counters.transferred;
1002 info->ram->total = ram_bytes_total();
1003 info->ram->duplicate = ram_counters.duplicate;
1004 /* legacy value. It is not used anymore */
1005 info->ram->skipped = 0;
1006 info->ram->normal = ram_counters.normal;
1007 info->ram->normal_bytes = ram_counters.normal *
1008 qemu_target_page_size();
1009 info->ram->mbps = s->mbps;
1010 info->ram->dirty_sync_count = ram_counters.dirty_sync_count;
1011 info->ram->postcopy_requests = ram_counters.postcopy_requests;
1012 info->ram->page_size = qemu_target_page_size();
1013 info->ram->multifd_bytes = ram_counters.multifd_bytes;
1014 info->ram->pages_per_second = s->pages_per_second;
1016 if (migrate_use_xbzrle()) {
1017 info->has_xbzrle_cache = true;
1018 info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
1019 info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
1020 info->xbzrle_cache->bytes = xbzrle_counters.bytes;
1021 info->xbzrle_cache->pages = xbzrle_counters.pages;
1022 info->xbzrle_cache->cache_miss = xbzrle_counters.cache_miss;
1023 info->xbzrle_cache->cache_miss_rate = xbzrle_counters.cache_miss_rate;
1024 info->xbzrle_cache->encoding_rate = xbzrle_counters.encoding_rate;
1025 info->xbzrle_cache->overflow = xbzrle_counters.overflow;
1028 if (migrate_use_compression()) {
1029 info->has_compression = true;
1030 info->compression = g_malloc0(sizeof(*info->compression));
1031 info->compression->pages = compression_counters.pages;
1032 info->compression->busy = compression_counters.busy;
1033 info->compression->busy_rate = compression_counters.busy_rate;
1034 info->compression->compressed_size =
1035 compression_counters.compressed_size;
1036 info->compression->compression_rate =
1037 compression_counters.compression_rate;
1040 if (cpu_throttle_active()) {
1041 info->has_cpu_throttle_percentage = true;
1042 info->cpu_throttle_percentage = cpu_throttle_get_percentage();
1045 if (s->state != MIGRATION_STATUS_COMPLETED) {
1046 info->ram->remaining = ram_bytes_remaining();
1047 info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate;
1051 static void populate_disk_info(MigrationInfo *info)
1053 if (blk_mig_active()) {
1054 info->has_disk = true;
1055 info->disk = g_malloc0(sizeof(*info->disk));
1056 info->disk->transferred = blk_mig_bytes_transferred();
1057 info->disk->remaining = blk_mig_bytes_remaining();
1058 info->disk->total = blk_mig_bytes_total();
1062 static void populate_vfio_info(MigrationInfo *info)
1064 #ifdef CONFIG_VFIO
1065 if (vfio_mig_active()) {
1066 info->has_vfio = true;
1067 info->vfio = g_malloc0(sizeof(*info->vfio));
1068 info->vfio->transferred = vfio_mig_bytes_transferred();
1070 #endif
1073 static void fill_source_migration_info(MigrationInfo *info)
1075 MigrationState *s = migrate_get_current();
1077 info->blocked = migration_is_blocked(NULL);
1078 info->has_blocked_reasons = info->blocked;
1079 info->blocked_reasons = NULL;
1080 if (info->blocked) {
1081 GSList *cur_blocker = migration_blockers;
1084 * There are two types of reasons a migration might be blocked;
1085 * a) devices marked in VMState as non-migratable, and
1086 * b) Explicit migration blockers
1087 * We need to add both of them here.
1089 qemu_savevm_non_migratable_list(&info->blocked_reasons);
1091 while (cur_blocker) {
1092 QAPI_LIST_PREPEND(info->blocked_reasons,
1093 g_strdup(error_get_pretty(cur_blocker->data)));
1094 cur_blocker = g_slist_next(cur_blocker);
1098 switch (s->state) {
1099 case MIGRATION_STATUS_NONE:
1100 /* no migration has happened ever */
1101 /* do not overwrite destination migration status */
1102 return;
1103 case MIGRATION_STATUS_SETUP:
1104 info->has_status = true;
1105 info->has_total_time = false;
1106 break;
1107 case MIGRATION_STATUS_ACTIVE:
1108 case MIGRATION_STATUS_CANCELLING:
1109 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1110 case MIGRATION_STATUS_PRE_SWITCHOVER:
1111 case MIGRATION_STATUS_DEVICE:
1112 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1113 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1114 /* TODO add some postcopy stats */
1115 populate_time_info(info, s);
1116 populate_ram_info(info, s);
1117 populate_disk_info(info);
1118 populate_vfio_info(info);
1119 break;
1120 case MIGRATION_STATUS_COLO:
1121 info->has_status = true;
1122 /* TODO: display COLO specific information (checkpoint info etc.) */
1123 break;
1124 case MIGRATION_STATUS_COMPLETED:
1125 populate_time_info(info, s);
1126 populate_ram_info(info, s);
1127 populate_vfio_info(info);
1128 break;
1129 case MIGRATION_STATUS_FAILED:
1130 info->has_status = true;
1131 if (s->error) {
1132 info->has_error_desc = true;
1133 info->error_desc = g_strdup(error_get_pretty(s->error));
1135 break;
1136 case MIGRATION_STATUS_CANCELLED:
1137 info->has_status = true;
1138 break;
1139 case MIGRATION_STATUS_WAIT_UNPLUG:
1140 info->has_status = true;
1141 break;
1143 info->status = s->state;
1146 typedef enum WriteTrackingSupport {
1147 WT_SUPPORT_UNKNOWN = 0,
1148 WT_SUPPORT_ABSENT,
1149 WT_SUPPORT_AVAILABLE,
1150 WT_SUPPORT_COMPATIBLE
1151 } WriteTrackingSupport;
1153 static
1154 WriteTrackingSupport migrate_query_write_tracking(void)
1156 /* Check if kernel supports required UFFD features */
1157 if (!ram_write_tracking_available()) {
1158 return WT_SUPPORT_ABSENT;
1161 * Check if current memory configuration is
1162 * compatible with required UFFD features.
1164 if (!ram_write_tracking_compatible()) {
1165 return WT_SUPPORT_AVAILABLE;
1168 return WT_SUPPORT_COMPATIBLE;
1172 * @migration_caps_check - check capability validity
1174 * @cap_list: old capability list, array of bool
1175 * @params: new capabilities to be applied soon
1176 * @errp: set *errp if the check failed, with reason
1178 * Returns true if check passed, otherwise false.
1180 static bool migrate_caps_check(bool *cap_list,
1181 MigrationCapabilityStatusList *params,
1182 Error **errp)
1184 MigrationCapabilityStatusList *cap;
1185 bool old_postcopy_cap;
1186 MigrationIncomingState *mis = migration_incoming_get_current();
1188 old_postcopy_cap = cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM];
1190 for (cap = params; cap; cap = cap->next) {
1191 cap_list[cap->value->capability] = cap->value->state;
1194 #ifndef CONFIG_LIVE_BLOCK_MIGRATION
1195 if (cap_list[MIGRATION_CAPABILITY_BLOCK]) {
1196 error_setg(errp, "QEMU compiled without old-style (blk/-b, inc/-i) "
1197 "block migration");
1198 error_append_hint(errp, "Use drive_mirror+NBD instead.\n");
1199 return false;
1201 #endif
1203 #ifndef CONFIG_REPLICATION
1204 if (cap_list[MIGRATION_CAPABILITY_X_COLO]) {
1205 error_setg(errp, "QEMU compiled without replication module"
1206 " can't enable COLO");
1207 error_append_hint(errp, "Please enable replication before COLO.\n");
1208 return false;
1210 #endif
1212 if (cap_list[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
1213 /* This check is reasonably expensive, so only when it's being
1214 * set the first time, also it's only the destination that needs
1215 * special support.
1217 if (!old_postcopy_cap && runstate_check(RUN_STATE_INMIGRATE) &&
1218 !postcopy_ram_supported_by_host(mis)) {
1219 /* postcopy_ram_supported_by_host will have emitted a more
1220 * detailed message
1222 error_setg(errp, "Postcopy is not supported");
1223 return false;
1226 if (cap_list[MIGRATION_CAPABILITY_X_IGNORE_SHARED]) {
1227 error_setg(errp, "Postcopy is not compatible with ignore-shared");
1228 return false;
1232 if (cap_list[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT]) {
1233 WriteTrackingSupport wt_support;
1234 int idx;
1236 * Check if 'background-snapshot' capability is supported by
1237 * host kernel and compatible with guest memory configuration.
1239 wt_support = migrate_query_write_tracking();
1240 if (wt_support < WT_SUPPORT_AVAILABLE) {
1241 error_setg(errp, "Background-snapshot is not supported by host kernel");
1242 return false;
1244 if (wt_support < WT_SUPPORT_COMPATIBLE) {
1245 error_setg(errp, "Background-snapshot is not compatible "
1246 "with guest memory configuration");
1247 return false;
1251 * Check if there are any migration capabilities
1252 * incompatible with 'background-snapshot'.
1254 for (idx = 0; idx < check_caps_background_snapshot.size; idx++) {
1255 int incomp_cap = check_caps_background_snapshot.caps[idx];
1256 if (cap_list[incomp_cap]) {
1257 error_setg(errp,
1258 "Background-snapshot is not compatible with %s",
1259 MigrationCapability_str(incomp_cap));
1260 return false;
1265 return true;
1268 static void fill_destination_migration_info(MigrationInfo *info)
1270 MigrationIncomingState *mis = migration_incoming_get_current();
1272 if (mis->socket_address_list) {
1273 info->has_socket_address = true;
1274 info->socket_address =
1275 QAPI_CLONE(SocketAddressList, mis->socket_address_list);
1278 switch (mis->state) {
1279 case MIGRATION_STATUS_NONE:
1280 return;
1281 case MIGRATION_STATUS_SETUP:
1282 case MIGRATION_STATUS_CANCELLING:
1283 case MIGRATION_STATUS_CANCELLED:
1284 case MIGRATION_STATUS_ACTIVE:
1285 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1286 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1287 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1288 case MIGRATION_STATUS_FAILED:
1289 case MIGRATION_STATUS_COLO:
1290 info->has_status = true;
1291 break;
1292 case MIGRATION_STATUS_COMPLETED:
1293 info->has_status = true;
1294 fill_destination_postcopy_migration_info(info);
1295 break;
1297 info->status = mis->state;
1300 MigrationInfo *qmp_query_migrate(Error **errp)
1302 MigrationInfo *info = g_malloc0(sizeof(*info));
1304 fill_destination_migration_info(info);
1305 fill_source_migration_info(info);
1307 return info;
1310 void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
1311 Error **errp)
1313 MigrationState *s = migrate_get_current();
1314 MigrationCapabilityStatusList *cap;
1315 bool cap_list[MIGRATION_CAPABILITY__MAX];
1317 if (migration_is_running(s->state)) {
1318 error_setg(errp, QERR_MIGRATION_ACTIVE);
1319 return;
1322 memcpy(cap_list, s->enabled_capabilities, sizeof(cap_list));
1323 if (!migrate_caps_check(cap_list, params, errp)) {
1324 return;
1327 for (cap = params; cap; cap = cap->next) {
1328 s->enabled_capabilities[cap->value->capability] = cap->value->state;
1333 * Check whether the parameters are valid. Error will be put into errp
1334 * (if provided). Return true if valid, otherwise false.
1336 static bool migrate_params_check(MigrationParameters *params, Error **errp)
1338 if (params->has_compress_level &&
1339 (params->compress_level > 9)) {
1340 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "compress_level",
1341 "a value between 0 and 9");
1342 return false;
1345 if (params->has_compress_threads && (params->compress_threads < 1)) {
1346 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1347 "compress_threads",
1348 "a value between 1 and 255");
1349 return false;
1352 if (params->has_decompress_threads && (params->decompress_threads < 1)) {
1353 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1354 "decompress_threads",
1355 "a value between 1 and 255");
1356 return false;
1359 if (params->has_throttle_trigger_threshold &&
1360 (params->throttle_trigger_threshold < 1 ||
1361 params->throttle_trigger_threshold > 100)) {
1362 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1363 "throttle_trigger_threshold",
1364 "an integer in the range of 1 to 100");
1365 return false;
1368 if (params->has_cpu_throttle_initial &&
1369 (params->cpu_throttle_initial < 1 ||
1370 params->cpu_throttle_initial > 99)) {
1371 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1372 "cpu_throttle_initial",
1373 "an integer in the range of 1 to 99");
1374 return false;
1377 if (params->has_cpu_throttle_increment &&
1378 (params->cpu_throttle_increment < 1 ||
1379 params->cpu_throttle_increment > 99)) {
1380 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1381 "cpu_throttle_increment",
1382 "an integer in the range of 1 to 99");
1383 return false;
1386 if (params->has_max_bandwidth && (params->max_bandwidth > SIZE_MAX)) {
1387 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1388 "max_bandwidth",
1389 "an integer in the range of 0 to "stringify(SIZE_MAX)
1390 " bytes/second");
1391 return false;
1394 if (params->has_downtime_limit &&
1395 (params->downtime_limit > MAX_MIGRATE_DOWNTIME)) {
1396 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1397 "downtime_limit",
1398 "an integer in the range of 0 to "
1399 stringify(MAX_MIGRATE_DOWNTIME)" ms");
1400 return false;
1403 /* x_checkpoint_delay is now always positive */
1405 if (params->has_multifd_channels && (params->multifd_channels < 1)) {
1406 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1407 "multifd_channels",
1408 "a value between 1 and 255");
1409 return false;
1412 if (params->has_multifd_zlib_level &&
1413 (params->multifd_zlib_level > 9)) {
1414 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zlib_level",
1415 "a value between 0 and 9");
1416 return false;
1419 if (params->has_multifd_zstd_level &&
1420 (params->multifd_zstd_level > 20)) {
1421 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "multifd_zstd_level",
1422 "a value between 0 and 20");
1423 return false;
1426 if (params->has_xbzrle_cache_size &&
1427 (params->xbzrle_cache_size < qemu_target_page_size() ||
1428 !is_power_of_2(params->xbzrle_cache_size))) {
1429 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1430 "xbzrle_cache_size",
1431 "a power of two no less than the target page size");
1432 return false;
1435 if (params->has_max_cpu_throttle &&
1436 (params->max_cpu_throttle < params->cpu_throttle_initial ||
1437 params->max_cpu_throttle > 99)) {
1438 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1439 "max_cpu_throttle",
1440 "an integer in the range of cpu_throttle_initial to 99");
1441 return false;
1444 if (params->has_announce_initial &&
1445 params->announce_initial > 100000) {
1446 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1447 "announce_initial",
1448 "a value between 0 and 100000");
1449 return false;
1451 if (params->has_announce_max &&
1452 params->announce_max > 100000) {
1453 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1454 "announce_max",
1455 "a value between 0 and 100000");
1456 return false;
1458 if (params->has_announce_rounds &&
1459 params->announce_rounds > 1000) {
1460 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1461 "announce_rounds",
1462 "a value between 0 and 1000");
1463 return false;
1465 if (params->has_announce_step &&
1466 (params->announce_step < 1 ||
1467 params->announce_step > 10000)) {
1468 error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
1469 "announce_step",
1470 "a value between 0 and 10000");
1471 return false;
1474 if (params->has_block_bitmap_mapping &&
1475 !check_dirty_bitmap_mig_alias_map(params->block_bitmap_mapping, errp)) {
1476 error_prepend(errp, "Invalid mapping given for block-bitmap-mapping: ");
1477 return false;
1480 return true;
1483 static void migrate_params_test_apply(MigrateSetParameters *params,
1484 MigrationParameters *dest)
1486 *dest = migrate_get_current()->parameters;
1488 /* TODO use QAPI_CLONE() instead of duplicating it inline */
1490 if (params->has_compress_level) {
1491 dest->compress_level = params->compress_level;
1494 if (params->has_compress_threads) {
1495 dest->compress_threads = params->compress_threads;
1498 if (params->has_compress_wait_thread) {
1499 dest->compress_wait_thread = params->compress_wait_thread;
1502 if (params->has_decompress_threads) {
1503 dest->decompress_threads = params->decompress_threads;
1506 if (params->has_throttle_trigger_threshold) {
1507 dest->throttle_trigger_threshold = params->throttle_trigger_threshold;
1510 if (params->has_cpu_throttle_initial) {
1511 dest->cpu_throttle_initial = params->cpu_throttle_initial;
1514 if (params->has_cpu_throttle_increment) {
1515 dest->cpu_throttle_increment = params->cpu_throttle_increment;
1518 if (params->has_cpu_throttle_tailslow) {
1519 dest->cpu_throttle_tailslow = params->cpu_throttle_tailslow;
1522 if (params->has_tls_creds) {
1523 assert(params->tls_creds->type == QTYPE_QSTRING);
1524 dest->tls_creds = params->tls_creds->u.s;
1527 if (params->has_tls_hostname) {
1528 assert(params->tls_hostname->type == QTYPE_QSTRING);
1529 dest->tls_hostname = params->tls_hostname->u.s;
1532 if (params->has_max_bandwidth) {
1533 dest->max_bandwidth = params->max_bandwidth;
1536 if (params->has_downtime_limit) {
1537 dest->downtime_limit = params->downtime_limit;
1540 if (params->has_x_checkpoint_delay) {
1541 dest->x_checkpoint_delay = params->x_checkpoint_delay;
1544 if (params->has_block_incremental) {
1545 dest->block_incremental = params->block_incremental;
1547 if (params->has_multifd_channels) {
1548 dest->multifd_channels = params->multifd_channels;
1550 if (params->has_multifd_compression) {
1551 dest->multifd_compression = params->multifd_compression;
1553 if (params->has_xbzrle_cache_size) {
1554 dest->xbzrle_cache_size = params->xbzrle_cache_size;
1556 if (params->has_max_postcopy_bandwidth) {
1557 dest->max_postcopy_bandwidth = params->max_postcopy_bandwidth;
1559 if (params->has_max_cpu_throttle) {
1560 dest->max_cpu_throttle = params->max_cpu_throttle;
1562 if (params->has_announce_initial) {
1563 dest->announce_initial = params->announce_initial;
1565 if (params->has_announce_max) {
1566 dest->announce_max = params->announce_max;
1568 if (params->has_announce_rounds) {
1569 dest->announce_rounds = params->announce_rounds;
1571 if (params->has_announce_step) {
1572 dest->announce_step = params->announce_step;
1575 if (params->has_block_bitmap_mapping) {
1576 dest->has_block_bitmap_mapping = true;
1577 dest->block_bitmap_mapping = params->block_bitmap_mapping;
1581 static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
1583 MigrationState *s = migrate_get_current();
1585 /* TODO use QAPI_CLONE() instead of duplicating it inline */
1587 if (params->has_compress_level) {
1588 s->parameters.compress_level = params->compress_level;
1591 if (params->has_compress_threads) {
1592 s->parameters.compress_threads = params->compress_threads;
1595 if (params->has_compress_wait_thread) {
1596 s->parameters.compress_wait_thread = params->compress_wait_thread;
1599 if (params->has_decompress_threads) {
1600 s->parameters.decompress_threads = params->decompress_threads;
1603 if (params->has_throttle_trigger_threshold) {
1604 s->parameters.throttle_trigger_threshold = params->throttle_trigger_threshold;
1607 if (params->has_cpu_throttle_initial) {
1608 s->parameters.cpu_throttle_initial = params->cpu_throttle_initial;
1611 if (params->has_cpu_throttle_increment) {
1612 s->parameters.cpu_throttle_increment = params->cpu_throttle_increment;
1615 if (params->has_cpu_throttle_tailslow) {
1616 s->parameters.cpu_throttle_tailslow = params->cpu_throttle_tailslow;
1619 if (params->has_tls_creds) {
1620 g_free(s->parameters.tls_creds);
1621 assert(params->tls_creds->type == QTYPE_QSTRING);
1622 s->parameters.tls_creds = g_strdup(params->tls_creds->u.s);
1625 if (params->has_tls_hostname) {
1626 g_free(s->parameters.tls_hostname);
1627 assert(params->tls_hostname->type == QTYPE_QSTRING);
1628 s->parameters.tls_hostname = g_strdup(params->tls_hostname->u.s);
1631 if (params->has_tls_authz) {
1632 g_free(s->parameters.tls_authz);
1633 assert(params->tls_authz->type == QTYPE_QSTRING);
1634 s->parameters.tls_authz = g_strdup(params->tls_authz->u.s);
1637 if (params->has_max_bandwidth) {
1638 s->parameters.max_bandwidth = params->max_bandwidth;
1639 if (s->to_dst_file && !migration_in_postcopy()) {
1640 qemu_file_set_rate_limit(s->to_dst_file,
1641 s->parameters.max_bandwidth / XFER_LIMIT_RATIO);
1645 if (params->has_downtime_limit) {
1646 s->parameters.downtime_limit = params->downtime_limit;
1649 if (params->has_x_checkpoint_delay) {
1650 s->parameters.x_checkpoint_delay = params->x_checkpoint_delay;
1651 if (migration_in_colo_state()) {
1652 colo_checkpoint_notify(s);
1656 if (params->has_block_incremental) {
1657 s->parameters.block_incremental = params->block_incremental;
1659 if (params->has_multifd_channels) {
1660 s->parameters.multifd_channels = params->multifd_channels;
1662 if (params->has_multifd_compression) {
1663 s->parameters.multifd_compression = params->multifd_compression;
1665 if (params->has_xbzrle_cache_size) {
1666 s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
1667 xbzrle_cache_resize(params->xbzrle_cache_size, errp);
1669 if (params->has_max_postcopy_bandwidth) {
1670 s->parameters.max_postcopy_bandwidth = params->max_postcopy_bandwidth;
1671 if (s->to_dst_file && migration_in_postcopy()) {
1672 qemu_file_set_rate_limit(s->to_dst_file,
1673 s->parameters.max_postcopy_bandwidth / XFER_LIMIT_RATIO);
1676 if (params->has_max_cpu_throttle) {
1677 s->parameters.max_cpu_throttle = params->max_cpu_throttle;
1679 if (params->has_announce_initial) {
1680 s->parameters.announce_initial = params->announce_initial;
1682 if (params->has_announce_max) {
1683 s->parameters.announce_max = params->announce_max;
1685 if (params->has_announce_rounds) {
1686 s->parameters.announce_rounds = params->announce_rounds;
1688 if (params->has_announce_step) {
1689 s->parameters.announce_step = params->announce_step;
1692 if (params->has_block_bitmap_mapping) {
1693 qapi_free_BitmapMigrationNodeAliasList(
1694 s->parameters.block_bitmap_mapping);
1696 s->parameters.has_block_bitmap_mapping = true;
1697 s->parameters.block_bitmap_mapping =
1698 QAPI_CLONE(BitmapMigrationNodeAliasList,
1699 params->block_bitmap_mapping);
1703 void qmp_migrate_set_parameters(MigrateSetParameters *params, Error **errp)
1705 MigrationParameters tmp;
1707 /* TODO Rewrite "" to null instead */
1708 if (params->has_tls_creds
1709 && params->tls_creds->type == QTYPE_QNULL) {
1710 qobject_unref(params->tls_creds->u.n);
1711 params->tls_creds->type = QTYPE_QSTRING;
1712 params->tls_creds->u.s = strdup("");
1714 /* TODO Rewrite "" to null instead */
1715 if (params->has_tls_hostname
1716 && params->tls_hostname->type == QTYPE_QNULL) {
1717 qobject_unref(params->tls_hostname->u.n);
1718 params->tls_hostname->type = QTYPE_QSTRING;
1719 params->tls_hostname->u.s = strdup("");
1722 migrate_params_test_apply(params, &tmp);
1724 if (!migrate_params_check(&tmp, errp)) {
1725 /* Invalid parameter */
1726 return;
1729 migrate_params_apply(params, errp);
1733 void qmp_migrate_start_postcopy(Error **errp)
1735 MigrationState *s = migrate_get_current();
1737 if (!migrate_postcopy()) {
1738 error_setg(errp, "Enable postcopy with migrate_set_capability before"
1739 " the start of migration");
1740 return;
1743 if (s->state == MIGRATION_STATUS_NONE) {
1744 error_setg(errp, "Postcopy must be started after migration has been"
1745 " started");
1746 return;
1749 * we don't error if migration has finished since that would be racy
1750 * with issuing this command.
1752 qatomic_set(&s->start_postcopy, true);
1755 /* shared migration helpers */
1757 void migrate_set_state(int *state, int old_state, int new_state)
1759 assert(new_state < MIGRATION_STATUS__MAX);
1760 if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
1761 trace_migrate_set_state(MigrationStatus_str(new_state));
1762 migrate_generate_event(new_state);
1766 static MigrationCapabilityStatus *migrate_cap_add(MigrationCapability index,
1767 bool state)
1769 MigrationCapabilityStatus *cap;
1771 cap = g_new0(MigrationCapabilityStatus, 1);
1772 cap->capability = index;
1773 cap->state = state;
1775 return cap;
1778 void migrate_set_block_enabled(bool value, Error **errp)
1780 MigrationCapabilityStatusList *cap = NULL;
1782 QAPI_LIST_PREPEND(cap, migrate_cap_add(MIGRATION_CAPABILITY_BLOCK, value));
1783 qmp_migrate_set_capabilities(cap, errp);
1784 qapi_free_MigrationCapabilityStatusList(cap);
1787 static void migrate_set_block_incremental(MigrationState *s, bool value)
1789 s->parameters.block_incremental = value;
1792 static void block_cleanup_parameters(MigrationState *s)
1794 if (s->must_remove_block_options) {
1795 /* setting to false can never fail */
1796 migrate_set_block_enabled(false, &error_abort);
1797 migrate_set_block_incremental(s, false);
1798 s->must_remove_block_options = false;
1802 static void migrate_fd_cleanup(MigrationState *s)
1804 qemu_bh_delete(s->cleanup_bh);
1805 s->cleanup_bh = NULL;
1807 qemu_savevm_state_cleanup();
1809 if (s->to_dst_file) {
1810 QEMUFile *tmp;
1812 trace_migrate_fd_cleanup();
1813 qemu_mutex_unlock_iothread();
1814 if (s->migration_thread_running) {
1815 qemu_thread_join(&s->thread);
1816 s->migration_thread_running = false;
1818 qemu_mutex_lock_iothread();
1820 multifd_save_cleanup();
1821 qemu_mutex_lock(&s->qemu_file_lock);
1822 tmp = s->to_dst_file;
1823 s->to_dst_file = NULL;
1824 qemu_mutex_unlock(&s->qemu_file_lock);
1826 * Close the file handle without the lock to make sure the
1827 * critical section won't block for long.
1829 qemu_fclose(tmp);
1832 assert(!migration_is_active(s));
1834 if (s->state == MIGRATION_STATUS_CANCELLING) {
1835 migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING,
1836 MIGRATION_STATUS_CANCELLED);
1839 if (s->error) {
1840 /* It is used on info migrate. We can't free it */
1841 error_report_err(error_copy(s->error));
1843 notifier_list_notify(&migration_state_notifiers, s);
1844 block_cleanup_parameters(s);
1845 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
1848 static void migrate_fd_cleanup_schedule(MigrationState *s)
1851 * Ref the state for bh, because it may be called when
1852 * there're already no other refs
1854 object_ref(OBJECT(s));
1855 qemu_bh_schedule(s->cleanup_bh);
1858 static void migrate_fd_cleanup_bh(void *opaque)
1860 MigrationState *s = opaque;
1861 migrate_fd_cleanup(s);
1862 object_unref(OBJECT(s));
1865 void migrate_set_error(MigrationState *s, const Error *error)
1867 QEMU_LOCK_GUARD(&s->error_mutex);
1868 if (!s->error) {
1869 s->error = error_copy(error);
1873 void migrate_fd_error(MigrationState *s, const Error *error)
1875 trace_migrate_fd_error(error_get_pretty(error));
1876 assert(s->to_dst_file == NULL);
1877 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
1878 MIGRATION_STATUS_FAILED);
1879 migrate_set_error(s, error);
1882 static void migrate_fd_cancel(MigrationState *s)
1884 int old_state ;
1885 QEMUFile *f = migrate_get_current()->to_dst_file;
1886 trace_migrate_fd_cancel();
1888 if (s->rp_state.from_dst_file) {
1889 /* shutdown the rp socket, so causing the rp thread to shutdown */
1890 qemu_file_shutdown(s->rp_state.from_dst_file);
1893 do {
1894 old_state = s->state;
1895 if (!migration_is_running(old_state)) {
1896 break;
1898 /* If the migration is paused, kick it out of the pause */
1899 if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) {
1900 qemu_sem_post(&s->pause_sem);
1902 migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING);
1903 } while (s->state != MIGRATION_STATUS_CANCELLING);
1906 * If we're unlucky the migration code might be stuck somewhere in a
1907 * send/write while the network has failed and is waiting to timeout;
1908 * if we've got shutdown(2) available then we can force it to quit.
1909 * The outgoing qemu file gets closed in migrate_fd_cleanup that is
1910 * called in a bh, so there is no race against this cancel.
1912 if (s->state == MIGRATION_STATUS_CANCELLING && f) {
1913 qemu_file_shutdown(f);
1915 if (s->state == MIGRATION_STATUS_CANCELLING && s->block_inactive) {
1916 Error *local_err = NULL;
1918 bdrv_invalidate_cache_all(&local_err);
1919 if (local_err) {
1920 error_report_err(local_err);
1921 } else {
1922 s->block_inactive = false;
1927 void add_migration_state_change_notifier(Notifier *notify)
1929 notifier_list_add(&migration_state_notifiers, notify);
1932 void remove_migration_state_change_notifier(Notifier *notify)
1934 notifier_remove(notify);
1937 bool migration_in_setup(MigrationState *s)
1939 return s->state == MIGRATION_STATUS_SETUP;
1942 bool migration_has_finished(MigrationState *s)
1944 return s->state == MIGRATION_STATUS_COMPLETED;
1947 bool migration_has_failed(MigrationState *s)
1949 return (s->state == MIGRATION_STATUS_CANCELLED ||
1950 s->state == MIGRATION_STATUS_FAILED);
1953 bool migration_in_postcopy(void)
1955 MigrationState *s = migrate_get_current();
1957 switch (s->state) {
1958 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
1959 case MIGRATION_STATUS_POSTCOPY_PAUSED:
1960 case MIGRATION_STATUS_POSTCOPY_RECOVER:
1961 return true;
1962 default:
1963 return false;
1967 bool migration_in_postcopy_after_devices(MigrationState *s)
1969 return migration_in_postcopy() && s->postcopy_after_devices;
1972 bool migration_in_incoming_postcopy(void)
1974 PostcopyState ps = postcopy_state_get();
1976 return ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END;
1979 bool migration_in_bg_snapshot(void)
1981 MigrationState *s = migrate_get_current();
1983 return migrate_background_snapshot() &&
1984 migration_is_setup_or_active(s->state);
1987 bool migration_is_idle(void)
1989 MigrationState *s = current_migration;
1991 if (!s) {
1992 return true;
1995 switch (s->state) {
1996 case MIGRATION_STATUS_NONE:
1997 case MIGRATION_STATUS_CANCELLED:
1998 case MIGRATION_STATUS_COMPLETED:
1999 case MIGRATION_STATUS_FAILED:
2000 return true;
2001 case MIGRATION_STATUS_SETUP:
2002 case MIGRATION_STATUS_CANCELLING:
2003 case MIGRATION_STATUS_ACTIVE:
2004 case MIGRATION_STATUS_POSTCOPY_ACTIVE:
2005 case MIGRATION_STATUS_COLO:
2006 case MIGRATION_STATUS_PRE_SWITCHOVER:
2007 case MIGRATION_STATUS_DEVICE:
2008 case MIGRATION_STATUS_WAIT_UNPLUG:
2009 return false;
2010 case MIGRATION_STATUS__MAX:
2011 g_assert_not_reached();
2014 return false;
2017 bool migration_is_active(MigrationState *s)
2019 return (s->state == MIGRATION_STATUS_ACTIVE ||
2020 s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
2023 void migrate_init(MigrationState *s)
2026 * Reinitialise all migration state, except
2027 * parameters/capabilities that the user set, and
2028 * locks.
2030 s->cleanup_bh = 0;
2031 s->vm_start_bh = 0;
2032 s->to_dst_file = NULL;
2033 s->state = MIGRATION_STATUS_NONE;
2034 s->rp_state.from_dst_file = NULL;
2035 s->rp_state.error = false;
2036 s->mbps = 0.0;
2037 s->pages_per_second = 0.0;
2038 s->downtime = 0;
2039 s->expected_downtime = 0;
2040 s->setup_time = 0;
2041 s->start_postcopy = false;
2042 s->postcopy_after_devices = false;
2043 s->migration_thread_running = false;
2044 error_free(s->error);
2045 s->error = NULL;
2046 s->hostname = NULL;
2048 migrate_set_state(&s->state, MIGRATION_STATUS_NONE, MIGRATION_STATUS_SETUP);
2050 s->start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
2051 s->total_time = 0;
2052 s->vm_was_running = false;
2053 s->iteration_initial_bytes = 0;
2054 s->threshold_size = 0;
2057 int migrate_add_blocker(Error *reason, Error **errp)
2059 if (only_migratable) {
2060 error_propagate_prepend(errp, error_copy(reason),
2061 "disallowing migration blocker "
2062 "(--only-migratable) for: ");
2063 return -EACCES;
2066 if (migration_is_idle()) {
2067 migration_blockers = g_slist_prepend(migration_blockers, reason);
2068 return 0;
2071 error_propagate_prepend(errp, error_copy(reason),
2072 "disallowing migration blocker "
2073 "(migration in progress) for: ");
2074 return -EBUSY;
2077 void migrate_del_blocker(Error *reason)
2079 migration_blockers = g_slist_remove(migration_blockers, reason);
2082 void qmp_migrate_incoming(const char *uri, Error **errp)
2084 Error *local_err = NULL;
2085 static bool once = true;
2087 if (!once) {
2088 error_setg(errp, "The incoming migration has already been started");
2089 return;
2091 if (!runstate_check(RUN_STATE_INMIGRATE)) {
2092 error_setg(errp, "'-incoming' was not specified on the command line");
2093 return;
2096 qemu_start_incoming_migration(uri, &local_err);
2098 if (local_err) {
2099 error_propagate(errp, local_err);
2100 return;
2103 once = false;
2106 void qmp_migrate_recover(const char *uri, Error **errp)
2108 MigrationIncomingState *mis = migration_incoming_get_current();
2110 if (mis->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
2111 error_setg(errp, "Migrate recover can only be run "
2112 "when postcopy is paused.");
2113 return;
2116 if (qatomic_cmpxchg(&mis->postcopy_recover_triggered,
2117 false, true) == true) {
2118 error_setg(errp, "Migrate recovery is triggered already");
2119 return;
2123 * Note that this call will never start a real migration; it will
2124 * only re-setup the migration stream and poke existing migration
2125 * to continue using that newly established channel.
2127 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2128 qemu_start_incoming_migration(uri, errp);
2131 void qmp_migrate_pause(Error **errp)
2133 MigrationState *ms = migrate_get_current();
2134 MigrationIncomingState *mis = migration_incoming_get_current();
2135 int ret;
2137 if (ms->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
2138 /* Source side, during postcopy */
2139 qemu_mutex_lock(&ms->qemu_file_lock);
2140 ret = qemu_file_shutdown(ms->to_dst_file);
2141 qemu_mutex_unlock(&ms->qemu_file_lock);
2142 if (ret) {
2143 error_setg(errp, "Failed to pause source migration");
2145 return;
2148 if (mis->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
2149 ret = qemu_file_shutdown(mis->from_src_file);
2150 if (ret) {
2151 error_setg(errp, "Failed to pause destination migration");
2153 return;
2156 error_setg(errp, "migrate-pause is currently only supported "
2157 "during postcopy-active state");
2160 bool migration_is_blocked(Error **errp)
2162 if (qemu_savevm_state_blocked(errp)) {
2163 return true;
2166 if (migration_blockers) {
2167 error_propagate(errp, error_copy(migration_blockers->data));
2168 return true;
2171 return false;
2174 /* Returns true if continue to migrate, or false if error detected */
2175 static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
2176 bool resume, Error **errp)
2178 Error *local_err = NULL;
2180 if (resume) {
2181 if (s->state != MIGRATION_STATUS_POSTCOPY_PAUSED) {
2182 error_setg(errp, "Cannot resume if there is no "
2183 "paused migration");
2184 return false;
2188 * Postcopy recovery won't work well with release-ram
2189 * capability since release-ram will drop the page buffer as
2190 * long as the page is put into the send buffer. So if there
2191 * is a network failure happened, any page buffers that have
2192 * not yet reached the destination VM but have already been
2193 * sent from the source VM will be lost forever. Let's refuse
2194 * the client from resuming such a postcopy migration.
2195 * Luckily release-ram was designed to only be used when src
2196 * and destination VMs are on the same host, so it should be
2197 * fine.
2199 if (migrate_release_ram()) {
2200 error_setg(errp, "Postcopy recovery cannot work "
2201 "when release-ram capability is set");
2202 return false;
2205 /* This is a resume, skip init status */
2206 return true;
2209 if (migration_is_running(s->state)) {
2210 error_setg(errp, QERR_MIGRATION_ACTIVE);
2211 return false;
2214 if (runstate_check(RUN_STATE_INMIGRATE)) {
2215 error_setg(errp, "Guest is waiting for an incoming migration");
2216 return false;
2219 if (runstate_check(RUN_STATE_POSTMIGRATE)) {
2220 error_setg(errp, "Can't migrate the vm that was paused due to "
2221 "previous migration");
2222 return false;
2225 if (migration_is_blocked(errp)) {
2226 return false;
2229 if (blk || blk_inc) {
2230 if (migrate_use_block() || migrate_use_block_incremental()) {
2231 error_setg(errp, "Command options are incompatible with "
2232 "current migration capabilities");
2233 return false;
2235 migrate_set_block_enabled(true, &local_err);
2236 if (local_err) {
2237 error_propagate(errp, local_err);
2238 return false;
2240 s->must_remove_block_options = true;
2243 if (blk_inc) {
2244 migrate_set_block_incremental(s, true);
2247 migrate_init(s);
2249 * set ram_counters memory to zero for a
2250 * new migration
2252 memset(&ram_counters, 0, sizeof(ram_counters));
2254 return true;
2257 void qmp_migrate(const char *uri, bool has_blk, bool blk,
2258 bool has_inc, bool inc, bool has_detach, bool detach,
2259 bool has_resume, bool resume, Error **errp)
2261 Error *local_err = NULL;
2262 MigrationState *s = migrate_get_current();
2263 const char *p = NULL;
2265 if (!migrate_prepare(s, has_blk && blk, has_inc && inc,
2266 has_resume && resume, errp)) {
2267 /* Error detected, put into errp */
2268 return;
2271 if (!(has_resume && resume)) {
2272 if (!yank_register_instance(MIGRATION_YANK_INSTANCE, errp)) {
2273 return;
2277 if (strstart(uri, "tcp:", &p) ||
2278 strstart(uri, "unix:", NULL) ||
2279 strstart(uri, "vsock:", NULL)) {
2280 socket_start_outgoing_migration(s, p ? p : uri, &local_err);
2281 #ifdef CONFIG_RDMA
2282 } else if (strstart(uri, "rdma:", &p)) {
2283 rdma_start_outgoing_migration(s, p, &local_err);
2284 #endif
2285 } else if (strstart(uri, "exec:", &p)) {
2286 exec_start_outgoing_migration(s, p, &local_err);
2287 } else if (strstart(uri, "fd:", &p)) {
2288 fd_start_outgoing_migration(s, p, &local_err);
2289 } else {
2290 if (!(has_resume && resume)) {
2291 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2293 error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "uri",
2294 "a valid migration protocol");
2295 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
2296 MIGRATION_STATUS_FAILED);
2297 block_cleanup_parameters(s);
2298 return;
2301 if (local_err) {
2302 if (!(has_resume && resume)) {
2303 yank_unregister_instance(MIGRATION_YANK_INSTANCE);
2305 migrate_fd_error(s, local_err);
2306 error_propagate(errp, local_err);
2307 return;
2311 void qmp_migrate_cancel(Error **errp)
2313 migrate_fd_cancel(migrate_get_current());
2316 void qmp_migrate_continue(MigrationStatus state, Error **errp)
2318 MigrationState *s = migrate_get_current();
2319 if (s->state != state) {
2320 error_setg(errp, "Migration not in expected state: %s",
2321 MigrationStatus_str(s->state));
2322 return;
2324 qemu_sem_post(&s->pause_sem);
2327 bool migrate_release_ram(void)
2329 MigrationState *s;
2331 s = migrate_get_current();
2333 return s->enabled_capabilities[MIGRATION_CAPABILITY_RELEASE_RAM];
2336 bool migrate_postcopy_ram(void)
2338 MigrationState *s;
2340 s = migrate_get_current();
2342 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_RAM];
2345 bool migrate_postcopy(void)
2347 return migrate_postcopy_ram() || migrate_dirty_bitmaps();
2350 bool migrate_auto_converge(void)
2352 MigrationState *s;
2354 s = migrate_get_current();
2356 return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
2359 bool migrate_zero_blocks(void)
2361 MigrationState *s;
2363 s = migrate_get_current();
2365 return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
2368 bool migrate_postcopy_blocktime(void)
2370 MigrationState *s;
2372 s = migrate_get_current();
2374 return s->enabled_capabilities[MIGRATION_CAPABILITY_POSTCOPY_BLOCKTIME];
2377 bool migrate_use_compression(void)
2379 MigrationState *s;
2381 s = migrate_get_current();
2383 return s->enabled_capabilities[MIGRATION_CAPABILITY_COMPRESS];
2386 int migrate_compress_level(void)
2388 MigrationState *s;
2390 s = migrate_get_current();
2392 return s->parameters.compress_level;
2395 int migrate_compress_threads(void)
2397 MigrationState *s;
2399 s = migrate_get_current();
2401 return s->parameters.compress_threads;
2404 int migrate_compress_wait_thread(void)
2406 MigrationState *s;
2408 s = migrate_get_current();
2410 return s->parameters.compress_wait_thread;
2413 int migrate_decompress_threads(void)
2415 MigrationState *s;
2417 s = migrate_get_current();
2419 return s->parameters.decompress_threads;
2422 bool migrate_dirty_bitmaps(void)
2424 MigrationState *s;
2426 s = migrate_get_current();
2428 return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS];
2431 bool migrate_ignore_shared(void)
2433 MigrationState *s;
2435 s = migrate_get_current();
2437 return s->enabled_capabilities[MIGRATION_CAPABILITY_X_IGNORE_SHARED];
2440 bool migrate_validate_uuid(void)
2442 MigrationState *s;
2444 s = migrate_get_current();
2446 return s->enabled_capabilities[MIGRATION_CAPABILITY_VALIDATE_UUID];
2449 bool migrate_use_events(void)
2451 MigrationState *s;
2453 s = migrate_get_current();
2455 return s->enabled_capabilities[MIGRATION_CAPABILITY_EVENTS];
2458 bool migrate_use_multifd(void)
2460 MigrationState *s;
2462 s = migrate_get_current();
2464 return s->enabled_capabilities[MIGRATION_CAPABILITY_MULTIFD];
2467 bool migrate_pause_before_switchover(void)
2469 MigrationState *s;
2471 s = migrate_get_current();
2473 return s->enabled_capabilities[
2474 MIGRATION_CAPABILITY_PAUSE_BEFORE_SWITCHOVER];
2477 int migrate_multifd_channels(void)
2479 MigrationState *s;
2481 s = migrate_get_current();
2483 return s->parameters.multifd_channels;
2486 MultiFDCompression migrate_multifd_compression(void)
2488 MigrationState *s;
2490 s = migrate_get_current();
2492 return s->parameters.multifd_compression;
2495 int migrate_multifd_zlib_level(void)
2497 MigrationState *s;
2499 s = migrate_get_current();
2501 return s->parameters.multifd_zlib_level;
2504 int migrate_multifd_zstd_level(void)
2506 MigrationState *s;
2508 s = migrate_get_current();
2510 return s->parameters.multifd_zstd_level;
2513 int migrate_use_xbzrle(void)
2515 MigrationState *s;
2517 s = migrate_get_current();
2519 return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
2522 uint64_t migrate_xbzrle_cache_size(void)
2524 MigrationState *s;
2526 s = migrate_get_current();
2528 return s->parameters.xbzrle_cache_size;
2531 static int64_t migrate_max_postcopy_bandwidth(void)
2533 MigrationState *s;
2535 s = migrate_get_current();
2537 return s->parameters.max_postcopy_bandwidth;
2540 bool migrate_use_block(void)
2542 MigrationState *s;
2544 s = migrate_get_current();
2546 return s->enabled_capabilities[MIGRATION_CAPABILITY_BLOCK];
2549 bool migrate_use_return_path(void)
2551 MigrationState *s;
2553 s = migrate_get_current();
2555 return s->enabled_capabilities[MIGRATION_CAPABILITY_RETURN_PATH];
2558 bool migrate_use_block_incremental(void)
2560 MigrationState *s;
2562 s = migrate_get_current();
2564 return s->parameters.block_incremental;
2567 bool migrate_background_snapshot(void)
2569 MigrationState *s;
2571 s = migrate_get_current();
2573 return s->enabled_capabilities[MIGRATION_CAPABILITY_BACKGROUND_SNAPSHOT];
2576 /* migration thread support */
2578 * Something bad happened to the RP stream, mark an error
2579 * The caller shall print or trace something to indicate why
2581 static void mark_source_rp_bad(MigrationState *s)
2583 s->rp_state.error = true;
2586 static struct rp_cmd_args {
2587 ssize_t len; /* -1 = variable */
2588 const char *name;
2589 } rp_cmd_args[] = {
2590 [MIG_RP_MSG_INVALID] = { .len = -1, .name = "INVALID" },
2591 [MIG_RP_MSG_SHUT] = { .len = 4, .name = "SHUT" },
2592 [MIG_RP_MSG_PONG] = { .len = 4, .name = "PONG" },
2593 [MIG_RP_MSG_REQ_PAGES] = { .len = 12, .name = "REQ_PAGES" },
2594 [MIG_RP_MSG_REQ_PAGES_ID] = { .len = -1, .name = "REQ_PAGES_ID" },
2595 [MIG_RP_MSG_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
2596 [MIG_RP_MSG_RESUME_ACK] = { .len = 4, .name = "RESUME_ACK" },
2597 [MIG_RP_MSG_MAX] = { .len = -1, .name = "MAX" },
2601 * Process a request for pages received on the return path,
2602 * We're allowed to send more than requested (e.g. to round to our page size)
2603 * and we don't need to send pages that have already been sent.
2605 static void migrate_handle_rp_req_pages(MigrationState *ms, const char* rbname,
2606 ram_addr_t start, size_t len)
2608 long our_host_ps = qemu_real_host_page_size;
2610 trace_migrate_handle_rp_req_pages(rbname, start, len);
2613 * Since we currently insist on matching page sizes, just sanity check
2614 * we're being asked for whole host pages.
2616 if (start & (our_host_ps - 1) ||
2617 (len & (our_host_ps - 1))) {
2618 error_report("%s: Misaligned page request, start: " RAM_ADDR_FMT
2619 " len: %zd", __func__, start, len);
2620 mark_source_rp_bad(ms);
2621 return;
2624 if (ram_save_queue_pages(rbname, start, len)) {
2625 mark_source_rp_bad(ms);
2629 /* Return true to retry, false to quit */
2630 static bool postcopy_pause_return_path_thread(MigrationState *s)
2632 trace_postcopy_pause_return_path();
2634 qemu_sem_wait(&s->postcopy_pause_rp_sem);
2636 trace_postcopy_pause_return_path_continued();
2638 return true;
2641 static int migrate_handle_rp_recv_bitmap(MigrationState *s, char *block_name)
2643 RAMBlock *block = qemu_ram_block_by_name(block_name);
2645 if (!block) {
2646 error_report("%s: invalid block name '%s'", __func__, block_name);
2647 return -EINVAL;
2650 /* Fetch the received bitmap and refresh the dirty bitmap */
2651 return ram_dirty_bitmap_reload(s, block);
2654 static int migrate_handle_rp_resume_ack(MigrationState *s, uint32_t value)
2656 trace_source_return_path_thread_resume_ack(value);
2658 if (value != MIGRATION_RESUME_ACK_VALUE) {
2659 error_report("%s: illegal resume_ack value %"PRIu32,
2660 __func__, value);
2661 return -1;
2664 /* Now both sides are active. */
2665 migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
2666 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2668 /* Notify send thread that time to continue send pages */
2669 qemu_sem_post(&s->rp_state.rp_sem);
2671 return 0;
2675 * Handles messages sent on the return path towards the source VM
2678 static void *source_return_path_thread(void *opaque)
2680 MigrationState *ms = opaque;
2681 QEMUFile *rp = ms->rp_state.from_dst_file;
2682 uint16_t header_len, header_type;
2683 uint8_t buf[512];
2684 uint32_t tmp32, sibling_error;
2685 ram_addr_t start = 0; /* =0 to silence warning */
2686 size_t len = 0, expected_len;
2687 int res;
2689 trace_source_return_path_thread_entry();
2690 rcu_register_thread();
2692 retry:
2693 while (!ms->rp_state.error && !qemu_file_get_error(rp) &&
2694 migration_is_setup_or_active(ms->state)) {
2695 trace_source_return_path_thread_loop_top();
2696 header_type = qemu_get_be16(rp);
2697 header_len = qemu_get_be16(rp);
2699 if (qemu_file_get_error(rp)) {
2700 mark_source_rp_bad(ms);
2701 goto out;
2704 if (header_type >= MIG_RP_MSG_MAX ||
2705 header_type == MIG_RP_MSG_INVALID) {
2706 error_report("RP: Received invalid message 0x%04x length 0x%04x",
2707 header_type, header_len);
2708 mark_source_rp_bad(ms);
2709 goto out;
2712 if ((rp_cmd_args[header_type].len != -1 &&
2713 header_len != rp_cmd_args[header_type].len) ||
2714 header_len > sizeof(buf)) {
2715 error_report("RP: Received '%s' message (0x%04x) with"
2716 "incorrect length %d expecting %zu",
2717 rp_cmd_args[header_type].name, header_type, header_len,
2718 (size_t)rp_cmd_args[header_type].len);
2719 mark_source_rp_bad(ms);
2720 goto out;
2723 /* We know we've got a valid header by this point */
2724 res = qemu_get_buffer(rp, buf, header_len);
2725 if (res != header_len) {
2726 error_report("RP: Failed reading data for message 0x%04x"
2727 " read %d expected %d",
2728 header_type, res, header_len);
2729 mark_source_rp_bad(ms);
2730 goto out;
2733 /* OK, we have the message and the data */
2734 switch (header_type) {
2735 case MIG_RP_MSG_SHUT:
2736 sibling_error = ldl_be_p(buf);
2737 trace_source_return_path_thread_shut(sibling_error);
2738 if (sibling_error) {
2739 error_report("RP: Sibling indicated error %d", sibling_error);
2740 mark_source_rp_bad(ms);
2743 * We'll let the main thread deal with closing the RP
2744 * we could do a shutdown(2) on it, but we're the only user
2745 * anyway, so there's nothing gained.
2747 goto out;
2749 case MIG_RP_MSG_PONG:
2750 tmp32 = ldl_be_p(buf);
2751 trace_source_return_path_thread_pong(tmp32);
2752 break;
2754 case MIG_RP_MSG_REQ_PAGES:
2755 start = ldq_be_p(buf);
2756 len = ldl_be_p(buf + 8);
2757 migrate_handle_rp_req_pages(ms, NULL, start, len);
2758 break;
2760 case MIG_RP_MSG_REQ_PAGES_ID:
2761 expected_len = 12 + 1; /* header + termination */
2763 if (header_len >= expected_len) {
2764 start = ldq_be_p(buf);
2765 len = ldl_be_p(buf + 8);
2766 /* Now we expect an idstr */
2767 tmp32 = buf[12]; /* Length of the following idstr */
2768 buf[13 + tmp32] = '\0';
2769 expected_len += tmp32;
2771 if (header_len != expected_len) {
2772 error_report("RP: Req_Page_id with length %d expecting %zd",
2773 header_len, expected_len);
2774 mark_source_rp_bad(ms);
2775 goto out;
2777 migrate_handle_rp_req_pages(ms, (char *)&buf[13], start, len);
2778 break;
2780 case MIG_RP_MSG_RECV_BITMAP:
2781 if (header_len < 1) {
2782 error_report("%s: missing block name", __func__);
2783 mark_source_rp_bad(ms);
2784 goto out;
2786 /* Format: len (1B) + idstr (<255B). This ends the idstr. */
2787 buf[buf[0] + 1] = '\0';
2788 if (migrate_handle_rp_recv_bitmap(ms, (char *)(buf + 1))) {
2789 mark_source_rp_bad(ms);
2790 goto out;
2792 break;
2794 case MIG_RP_MSG_RESUME_ACK:
2795 tmp32 = ldl_be_p(buf);
2796 if (migrate_handle_rp_resume_ack(ms, tmp32)) {
2797 mark_source_rp_bad(ms);
2798 goto out;
2800 break;
2802 default:
2803 break;
2807 out:
2808 res = qemu_file_get_error(rp);
2809 if (res) {
2810 if (res == -EIO && migration_in_postcopy()) {
2812 * Maybe there is something we can do: it looks like a
2813 * network down issue, and we pause for a recovery.
2815 if (postcopy_pause_return_path_thread(ms)) {
2816 /* Reload rp, reset the rest */
2817 if (rp != ms->rp_state.from_dst_file) {
2818 qemu_fclose(rp);
2819 rp = ms->rp_state.from_dst_file;
2821 ms->rp_state.error = false;
2822 goto retry;
2826 trace_source_return_path_thread_bad_end();
2827 mark_source_rp_bad(ms);
2830 trace_source_return_path_thread_end();
2831 ms->rp_state.from_dst_file = NULL;
2832 qemu_fclose(rp);
2833 rcu_unregister_thread();
2834 return NULL;
2837 static int open_return_path_on_source(MigrationState *ms,
2838 bool create_thread)
2841 ms->rp_state.from_dst_file = qemu_file_get_return_path(ms->to_dst_file);
2842 if (!ms->rp_state.from_dst_file) {
2843 return -1;
2846 trace_open_return_path_on_source();
2848 if (!create_thread) {
2849 /* We're done */
2850 return 0;
2853 qemu_thread_create(&ms->rp_state.rp_thread, "return path",
2854 source_return_path_thread, ms, QEMU_THREAD_JOINABLE);
2856 trace_open_return_path_on_source_continue();
2858 return 0;
2861 /* Returns 0 if the RP was ok, otherwise there was an error on the RP */
2862 static int await_return_path_close_on_source(MigrationState *ms)
2865 * If this is a normal exit then the destination will send a SHUT and the
2866 * rp_thread will exit, however if there's an error we need to cause
2867 * it to exit.
2869 if (qemu_file_get_error(ms->to_dst_file) && ms->rp_state.from_dst_file) {
2871 * shutdown(2), if we have it, will cause it to unblock if it's stuck
2872 * waiting for the destination.
2874 qemu_file_shutdown(ms->rp_state.from_dst_file);
2875 mark_source_rp_bad(ms);
2877 trace_await_return_path_close_on_source_joining();
2878 qemu_thread_join(&ms->rp_state.rp_thread);
2879 trace_await_return_path_close_on_source_close();
2880 return ms->rp_state.error;
2884 * Switch from normal iteration to postcopy
2885 * Returns non-0 on error
2887 static int postcopy_start(MigrationState *ms)
2889 int ret;
2890 QIOChannelBuffer *bioc;
2891 QEMUFile *fb;
2892 int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
2893 int64_t bandwidth = migrate_max_postcopy_bandwidth();
2894 bool restart_block = false;
2895 int cur_state = MIGRATION_STATUS_ACTIVE;
2896 if (!migrate_pause_before_switchover()) {
2897 migrate_set_state(&ms->state, MIGRATION_STATUS_ACTIVE,
2898 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2901 trace_postcopy_start();
2902 qemu_mutex_lock_iothread();
2903 trace_postcopy_start_set_run();
2905 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
2906 global_state_store();
2907 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
2908 if (ret < 0) {
2909 goto fail;
2912 ret = migration_maybe_pause(ms, &cur_state,
2913 MIGRATION_STATUS_POSTCOPY_ACTIVE);
2914 if (ret < 0) {
2915 goto fail;
2918 ret = bdrv_inactivate_all();
2919 if (ret < 0) {
2920 goto fail;
2922 restart_block = true;
2925 * Cause any non-postcopiable, but iterative devices to
2926 * send out their final data.
2928 qemu_savevm_state_complete_precopy(ms->to_dst_file, true, false);
2931 * in Finish migrate and with the io-lock held everything should
2932 * be quiet, but we've potentially still got dirty pages and we
2933 * need to tell the destination to throw any pages it's already received
2934 * that are dirty
2936 if (migrate_postcopy_ram()) {
2937 if (ram_postcopy_send_discard_bitmap(ms)) {
2938 error_report("postcopy send discard bitmap failed");
2939 goto fail;
2944 * send rest of state - note things that are doing postcopy
2945 * will notice we're in POSTCOPY_ACTIVE and not actually
2946 * wrap their state up here
2948 /* 0 max-postcopy-bandwidth means unlimited */
2949 if (!bandwidth) {
2950 qemu_file_set_rate_limit(ms->to_dst_file, INT64_MAX);
2951 } else {
2952 qemu_file_set_rate_limit(ms->to_dst_file, bandwidth / XFER_LIMIT_RATIO);
2954 if (migrate_postcopy_ram()) {
2955 /* Ping just for debugging, helps line traces up */
2956 qemu_savevm_send_ping(ms->to_dst_file, 2);
2960 * While loading the device state we may trigger page transfer
2961 * requests and the fd must be free to process those, and thus
2962 * the destination must read the whole device state off the fd before
2963 * it starts processing it. Unfortunately the ad-hoc migration format
2964 * doesn't allow the destination to know the size to read without fully
2965 * parsing it through each devices load-state code (especially the open
2966 * coded devices that use get/put).
2967 * So we wrap the device state up in a package with a length at the start;
2968 * to do this we use a qemu_buf to hold the whole of the device state.
2970 bioc = qio_channel_buffer_new(4096);
2971 qio_channel_set_name(QIO_CHANNEL(bioc), "migration-postcopy-buffer");
2972 fb = qemu_fopen_channel_output(QIO_CHANNEL(bioc));
2973 object_unref(OBJECT(bioc));
2976 * Make sure the receiver can get incoming pages before we send the rest
2977 * of the state
2979 qemu_savevm_send_postcopy_listen(fb);
2981 qemu_savevm_state_complete_precopy(fb, false, false);
2982 if (migrate_postcopy_ram()) {
2983 qemu_savevm_send_ping(fb, 3);
2986 qemu_savevm_send_postcopy_run(fb);
2988 /* <><> end of stuff going into the package */
2990 /* Last point of recovery; as soon as we send the package the destination
2991 * can open devices and potentially start running.
2992 * Lets just check again we've not got any errors.
2994 ret = qemu_file_get_error(ms->to_dst_file);
2995 if (ret) {
2996 error_report("postcopy_start: Migration stream errored (pre package)");
2997 goto fail_closefb;
3000 restart_block = false;
3002 /* Now send that blob */
3003 if (qemu_savevm_send_packaged(ms->to_dst_file, bioc->data, bioc->usage)) {
3004 goto fail_closefb;
3006 qemu_fclose(fb);
3008 /* Send a notify to give a chance for anything that needs to happen
3009 * at the transition to postcopy and after the device state; in particular
3010 * spice needs to trigger a transition now
3012 ms->postcopy_after_devices = true;
3013 notifier_list_notify(&migration_state_notifiers, ms);
3015 ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop;
3017 qemu_mutex_unlock_iothread();
3019 if (migrate_postcopy_ram()) {
3021 * Although this ping is just for debug, it could potentially be
3022 * used for getting a better measurement of downtime at the source.
3024 qemu_savevm_send_ping(ms->to_dst_file, 4);
3027 if (migrate_release_ram()) {
3028 ram_postcopy_migrated_memory_release(ms);
3031 ret = qemu_file_get_error(ms->to_dst_file);
3032 if (ret) {
3033 error_report("postcopy_start: Migration stream errored");
3034 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
3035 MIGRATION_STATUS_FAILED);
3038 return ret;
3040 fail_closefb:
3041 qemu_fclose(fb);
3042 fail:
3043 migrate_set_state(&ms->state, MIGRATION_STATUS_POSTCOPY_ACTIVE,
3044 MIGRATION_STATUS_FAILED);
3045 if (restart_block) {
3046 /* A failure happened early enough that we know the destination hasn't
3047 * accessed block devices, so we're safe to recover.
3049 Error *local_err = NULL;
3051 bdrv_invalidate_cache_all(&local_err);
3052 if (local_err) {
3053 error_report_err(local_err);
3056 qemu_mutex_unlock_iothread();
3057 return -1;
3061 * migration_maybe_pause: Pause if required to by
3062 * migrate_pause_before_switchover called with the iothread locked
3063 * Returns: 0 on success
3065 static int migration_maybe_pause(MigrationState *s,
3066 int *current_active_state,
3067 int new_state)
3069 if (!migrate_pause_before_switchover()) {
3070 return 0;
3073 /* Since leaving this state is not atomic with posting the semaphore
3074 * it's possible that someone could have issued multiple migrate_continue
3075 * and the semaphore is incorrectly positive at this point;
3076 * the docs say it's undefined to reinit a semaphore that's already
3077 * init'd, so use timedwait to eat up any existing posts.
3079 while (qemu_sem_timedwait(&s->pause_sem, 1) == 0) {
3080 /* This block intentionally left blank */
3084 * If the migration is cancelled when it is in the completion phase,
3085 * the migration state is set to MIGRATION_STATUS_CANCELLING.
3086 * So we don't need to wait a semaphore, otherwise we would always
3087 * wait for the 'pause_sem' semaphore.
3089 if (s->state != MIGRATION_STATUS_CANCELLING) {
3090 qemu_mutex_unlock_iothread();
3091 migrate_set_state(&s->state, *current_active_state,
3092 MIGRATION_STATUS_PRE_SWITCHOVER);
3093 qemu_sem_wait(&s->pause_sem);
3094 migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER,
3095 new_state);
3096 *current_active_state = new_state;
3097 qemu_mutex_lock_iothread();
3100 return s->state == new_state ? 0 : -EINVAL;
3104 * migration_completion: Used by migration_thread when there's not much left.
3105 * The caller 'breaks' the loop when this returns.
3107 * @s: Current migration state
3109 static void migration_completion(MigrationState *s)
3111 int ret;
3112 int current_active_state = s->state;
3114 if (s->state == MIGRATION_STATUS_ACTIVE) {
3115 qemu_mutex_lock_iothread();
3116 s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3117 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
3118 s->vm_was_running = runstate_is_running();
3119 ret = global_state_store();
3121 if (!ret) {
3122 bool inactivate = !migrate_colo_enabled();
3123 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
3124 if (ret >= 0) {
3125 ret = migration_maybe_pause(s, &current_active_state,
3126 MIGRATION_STATUS_DEVICE);
3128 if (ret >= 0) {
3129 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
3130 ret = qemu_savevm_state_complete_precopy(s->to_dst_file, false,
3131 inactivate);
3133 if (inactivate && ret >= 0) {
3134 s->block_inactive = true;
3137 qemu_mutex_unlock_iothread();
3139 if (ret < 0) {
3140 goto fail;
3142 } else if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
3143 trace_migration_completion_postcopy_end();
3145 qemu_savevm_state_complete_postcopy(s->to_dst_file);
3146 trace_migration_completion_postcopy_end_after_complete();
3147 } else if (s->state == MIGRATION_STATUS_CANCELLING) {
3148 goto fail;
3152 * If rp was opened we must clean up the thread before
3153 * cleaning everything else up (since if there are no failures
3154 * it will wait for the destination to send it's status in
3155 * a SHUT command).
3157 if (s->rp_state.from_dst_file) {
3158 int rp_error;
3159 trace_migration_return_path_end_before();
3160 rp_error = await_return_path_close_on_source(s);
3161 trace_migration_return_path_end_after(rp_error);
3162 if (rp_error) {
3163 goto fail_invalidate;
3167 if (qemu_file_get_error(s->to_dst_file)) {
3168 trace_migration_completion_file_err();
3169 goto fail_invalidate;
3172 if (!migrate_colo_enabled()) {
3173 migrate_set_state(&s->state, current_active_state,
3174 MIGRATION_STATUS_COMPLETED);
3177 return;
3179 fail_invalidate:
3180 /* If not doing postcopy, vm_start() will be called: let's regain
3181 * control on images.
3183 if (s->state == MIGRATION_STATUS_ACTIVE ||
3184 s->state == MIGRATION_STATUS_DEVICE) {
3185 Error *local_err = NULL;
3187 qemu_mutex_lock_iothread();
3188 bdrv_invalidate_cache_all(&local_err);
3189 if (local_err) {
3190 error_report_err(local_err);
3191 } else {
3192 s->block_inactive = false;
3194 qemu_mutex_unlock_iothread();
3197 fail:
3198 migrate_set_state(&s->state, current_active_state,
3199 MIGRATION_STATUS_FAILED);
3203 * bg_migration_completion: Used by bg_migration_thread when after all the
3204 * RAM has been saved. The caller 'breaks' the loop when this returns.
3206 * @s: Current migration state
3208 static void bg_migration_completion(MigrationState *s)
3210 int current_active_state = s->state;
3213 * Stop tracking RAM writes - un-protect memory, un-register UFFD
3214 * memory ranges, flush kernel wait queues and wake up threads
3215 * waiting for write fault to be resolved.
3217 ram_write_tracking_stop();
3219 if (s->state == MIGRATION_STATUS_ACTIVE) {
3221 * By this moment we have RAM content saved into the migration stream.
3222 * The next step is to flush the non-RAM content (device state)
3223 * right after the ram content. The device state has been stored into
3224 * the temporary buffer before RAM saving started.
3226 qemu_put_buffer(s->to_dst_file, s->bioc->data, s->bioc->usage);
3227 qemu_fflush(s->to_dst_file);
3228 } else if (s->state == MIGRATION_STATUS_CANCELLING) {
3229 goto fail;
3232 if (qemu_file_get_error(s->to_dst_file)) {
3233 trace_migration_completion_file_err();
3234 goto fail;
3237 migrate_set_state(&s->state, current_active_state,
3238 MIGRATION_STATUS_COMPLETED);
3239 return;
3241 fail:
3242 migrate_set_state(&s->state, current_active_state,
3243 MIGRATION_STATUS_FAILED);
3246 bool migrate_colo_enabled(void)
3248 MigrationState *s = migrate_get_current();
3249 return s->enabled_capabilities[MIGRATION_CAPABILITY_X_COLO];
3252 typedef enum MigThrError {
3253 /* No error detected */
3254 MIG_THR_ERR_NONE = 0,
3255 /* Detected error, but resumed successfully */
3256 MIG_THR_ERR_RECOVERED = 1,
3257 /* Detected fatal error, need to exit */
3258 MIG_THR_ERR_FATAL = 2,
3259 } MigThrError;
3261 static int postcopy_resume_handshake(MigrationState *s)
3263 qemu_savevm_send_postcopy_resume(s->to_dst_file);
3265 while (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
3266 qemu_sem_wait(&s->rp_state.rp_sem);
3269 if (s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE) {
3270 return 0;
3273 return -1;
3276 /* Return zero if success, or <0 for error */
3277 static int postcopy_do_resume(MigrationState *s)
3279 int ret;
3282 * Call all the resume_prepare() hooks, so that modules can be
3283 * ready for the migration resume.
3285 ret = qemu_savevm_state_resume_prepare(s);
3286 if (ret) {
3287 error_report("%s: resume_prepare() failure detected: %d",
3288 __func__, ret);
3289 return ret;
3293 * Last handshake with destination on the resume (destination will
3294 * switch to postcopy-active afterwards)
3296 ret = postcopy_resume_handshake(s);
3297 if (ret) {
3298 error_report("%s: handshake failed: %d", __func__, ret);
3299 return ret;
3302 return 0;
3306 * We don't return until we are in a safe state to continue current
3307 * postcopy migration. Returns MIG_THR_ERR_RECOVERED if recovered, or
3308 * MIG_THR_ERR_FATAL if unrecovery failure happened.
3310 static MigThrError postcopy_pause(MigrationState *s)
3312 assert(s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE);
3314 while (true) {
3315 QEMUFile *file;
3317 /* Current channel is possibly broken. Release it. */
3318 assert(s->to_dst_file);
3319 qemu_mutex_lock(&s->qemu_file_lock);
3320 file = s->to_dst_file;
3321 s->to_dst_file = NULL;
3322 qemu_mutex_unlock(&s->qemu_file_lock);
3324 qemu_file_shutdown(file);
3325 qemu_fclose(file);
3327 migrate_set_state(&s->state, s->state,
3328 MIGRATION_STATUS_POSTCOPY_PAUSED);
3330 error_report("Detected IO failure for postcopy. "
3331 "Migration paused.");
3334 * We wait until things fixed up. Then someone will setup the
3335 * status back for us.
3337 while (s->state == MIGRATION_STATUS_POSTCOPY_PAUSED) {
3338 qemu_sem_wait(&s->postcopy_pause_sem);
3341 if (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER) {
3342 /* Woken up by a recover procedure. Give it a shot */
3345 * Firstly, let's wake up the return path now, with a new
3346 * return path channel.
3348 qemu_sem_post(&s->postcopy_pause_rp_sem);
3350 /* Do the resume logic */
3351 if (postcopy_do_resume(s) == 0) {
3352 /* Let's continue! */
3353 trace_postcopy_pause_continued();
3354 return MIG_THR_ERR_RECOVERED;
3355 } else {
3357 * Something wrong happened during the recovery, let's
3358 * pause again. Pause is always better than throwing
3359 * data away.
3361 continue;
3363 } else {
3364 /* This is not right... Time to quit. */
3365 return MIG_THR_ERR_FATAL;
3370 static MigThrError migration_detect_error(MigrationState *s)
3372 int ret;
3373 int state = s->state;
3374 Error *local_error = NULL;
3376 if (state == MIGRATION_STATUS_CANCELLING ||
3377 state == MIGRATION_STATUS_CANCELLED) {
3378 /* End the migration, but don't set the state to failed */
3379 return MIG_THR_ERR_FATAL;
3382 /* Try to detect any file errors */
3383 ret = qemu_file_get_error_obj(s->to_dst_file, &local_error);
3384 if (!ret) {
3385 /* Everything is fine */
3386 assert(!local_error);
3387 return MIG_THR_ERR_NONE;
3390 if (local_error) {
3391 migrate_set_error(s, local_error);
3392 error_free(local_error);
3395 if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret == -EIO) {
3397 * For postcopy, we allow the network to be down for a
3398 * while. After that, it can be continued by a
3399 * recovery phase.
3401 return postcopy_pause(s);
3402 } else {
3404 * For precopy (or postcopy with error outside IO), we fail
3405 * with no time.
3407 migrate_set_state(&s->state, state, MIGRATION_STATUS_FAILED);
3408 trace_migration_thread_file_err();
3410 /* Time to stop the migration, now. */
3411 return MIG_THR_ERR_FATAL;
3415 /* How many bytes have we transferred since the beginning of the migration */
3416 static uint64_t migration_total_bytes(MigrationState *s)
3418 return qemu_ftell(s->to_dst_file) + ram_counters.multifd_bytes;
3421 static void migration_calculate_complete(MigrationState *s)
3423 uint64_t bytes = migration_total_bytes(s);
3424 int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3425 int64_t transfer_time;
3427 s->total_time = end_time - s->start_time;
3428 if (!s->downtime) {
3430 * It's still not set, so we are precopy migration. For
3431 * postcopy, downtime is calculated during postcopy_start().
3433 s->downtime = end_time - s->downtime_start;
3436 transfer_time = s->total_time - s->setup_time;
3437 if (transfer_time) {
3438 s->mbps = ((double) bytes * 8.0) / transfer_time / 1000;
3442 static void update_iteration_initial_status(MigrationState *s)
3445 * Update these three fields at the same time to avoid mismatch info lead
3446 * wrong speed calculation.
3448 s->iteration_start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3449 s->iteration_initial_bytes = migration_total_bytes(s);
3450 s->iteration_initial_pages = ram_get_total_transferred_pages();
3453 static void migration_update_counters(MigrationState *s,
3454 int64_t current_time)
3456 uint64_t transferred, transferred_pages, time_spent;
3457 uint64_t current_bytes; /* bytes transferred since the beginning */
3458 double bandwidth;
3460 if (current_time < s->iteration_start_time + BUFFER_DELAY) {
3461 return;
3464 current_bytes = migration_total_bytes(s);
3465 transferred = current_bytes - s->iteration_initial_bytes;
3466 time_spent = current_time - s->iteration_start_time;
3467 bandwidth = (double)transferred / time_spent;
3468 s->threshold_size = bandwidth * s->parameters.downtime_limit;
3470 s->mbps = (((double) transferred * 8.0) /
3471 ((double) time_spent / 1000.0)) / 1000.0 / 1000.0;
3473 transferred_pages = ram_get_total_transferred_pages() -
3474 s->iteration_initial_pages;
3475 s->pages_per_second = (double) transferred_pages /
3476 (((double) time_spent / 1000.0));
3479 * if we haven't sent anything, we don't want to
3480 * recalculate. 10000 is a small enough number for our purposes
3482 if (ram_counters.dirty_pages_rate && transferred > 10000) {
3483 s->expected_downtime = ram_counters.remaining / bandwidth;
3486 qemu_file_reset_rate_limit(s->to_dst_file);
3488 update_iteration_initial_status(s);
3490 trace_migrate_transferred(transferred, time_spent,
3491 bandwidth, s->threshold_size);
3494 /* Migration thread iteration status */
3495 typedef enum {
3496 MIG_ITERATE_RESUME, /* Resume current iteration */
3497 MIG_ITERATE_SKIP, /* Skip current iteration */
3498 MIG_ITERATE_BREAK, /* Break the loop */
3499 } MigIterateState;
3502 * Return true if continue to the next iteration directly, false
3503 * otherwise.
3505 static MigIterateState migration_iteration_run(MigrationState *s)
3507 uint64_t pending_size, pend_pre, pend_compat, pend_post;
3508 bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
3510 qemu_savevm_state_pending(s->to_dst_file, s->threshold_size, &pend_pre,
3511 &pend_compat, &pend_post);
3512 pending_size = pend_pre + pend_compat + pend_post;
3514 trace_migrate_pending(pending_size, s->threshold_size,
3515 pend_pre, pend_compat, pend_post);
3517 if (pending_size && pending_size >= s->threshold_size) {
3518 /* Still a significant amount to transfer */
3519 if (!in_postcopy && pend_pre <= s->threshold_size &&
3520 qatomic_read(&s->start_postcopy)) {
3521 if (postcopy_start(s)) {
3522 error_report("%s: postcopy failed to start", __func__);
3524 return MIG_ITERATE_SKIP;
3526 /* Just another iteration step */
3527 qemu_savevm_state_iterate(s->to_dst_file, in_postcopy);
3528 } else {
3529 trace_migration_thread_low_pending(pending_size);
3530 migration_completion(s);
3531 return MIG_ITERATE_BREAK;
3534 return MIG_ITERATE_RESUME;
3537 static void migration_iteration_finish(MigrationState *s)
3539 /* If we enabled cpu throttling for auto-converge, turn it off. */
3540 cpu_throttle_stop();
3542 qemu_mutex_lock_iothread();
3543 switch (s->state) {
3544 case MIGRATION_STATUS_COMPLETED:
3545 migration_calculate_complete(s);
3546 runstate_set(RUN_STATE_POSTMIGRATE);
3547 break;
3549 case MIGRATION_STATUS_ACTIVE:
3551 * We should really assert here, but since it's during
3552 * migration, let's try to reduce the usage of assertions.
3554 if (!migrate_colo_enabled()) {
3555 error_report("%s: critical error: calling COLO code without "
3556 "COLO enabled", __func__);
3558 migrate_start_colo_process(s);
3560 * Fixme: we will run VM in COLO no matter its old running state.
3561 * After exited COLO, we will keep running.
3563 s->vm_was_running = true;
3564 /* Fallthrough */
3565 case MIGRATION_STATUS_FAILED:
3566 case MIGRATION_STATUS_CANCELLED:
3567 case MIGRATION_STATUS_CANCELLING:
3568 if (s->vm_was_running) {
3569 vm_start();
3570 } else {
3571 if (runstate_check(RUN_STATE_FINISH_MIGRATE)) {
3572 runstate_set(RUN_STATE_POSTMIGRATE);
3575 break;
3577 default:
3578 /* Should not reach here, but if so, forgive the VM. */
3579 error_report("%s: Unknown ending state %d", __func__, s->state);
3580 break;
3582 migrate_fd_cleanup_schedule(s);
3583 qemu_mutex_unlock_iothread();
3586 static void bg_migration_iteration_finish(MigrationState *s)
3588 qemu_mutex_lock_iothread();
3589 switch (s->state) {
3590 case MIGRATION_STATUS_COMPLETED:
3591 migration_calculate_complete(s);
3592 break;
3594 case MIGRATION_STATUS_ACTIVE:
3595 case MIGRATION_STATUS_FAILED:
3596 case MIGRATION_STATUS_CANCELLED:
3597 case MIGRATION_STATUS_CANCELLING:
3598 break;
3600 default:
3601 /* Should not reach here, but if so, forgive the VM. */
3602 error_report("%s: Unknown ending state %d", __func__, s->state);
3603 break;
3606 migrate_fd_cleanup_schedule(s);
3607 qemu_mutex_unlock_iothread();
3611 * Return true if continue to the next iteration directly, false
3612 * otherwise.
3614 static MigIterateState bg_migration_iteration_run(MigrationState *s)
3616 int res;
3618 res = qemu_savevm_state_iterate(s->to_dst_file, false);
3619 if (res > 0) {
3620 bg_migration_completion(s);
3621 return MIG_ITERATE_BREAK;
3624 return MIG_ITERATE_RESUME;
3627 void migration_make_urgent_request(void)
3629 qemu_sem_post(&migrate_get_current()->rate_limit_sem);
3632 void migration_consume_urgent_request(void)
3634 qemu_sem_wait(&migrate_get_current()->rate_limit_sem);
3637 /* Returns true if the rate limiting was broken by an urgent request */
3638 bool migration_rate_limit(void)
3640 int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3641 MigrationState *s = migrate_get_current();
3643 bool urgent = false;
3644 migration_update_counters(s, now);
3645 if (qemu_file_rate_limit(s->to_dst_file)) {
3647 if (qemu_file_get_error(s->to_dst_file)) {
3648 return false;
3651 * Wait for a delay to do rate limiting OR
3652 * something urgent to post the semaphore.
3654 int ms = s->iteration_start_time + BUFFER_DELAY - now;
3655 trace_migration_rate_limit_pre(ms);
3656 if (qemu_sem_timedwait(&s->rate_limit_sem, ms) == 0) {
3658 * We were woken by one or more urgent things but
3659 * the timedwait will have consumed one of them.
3660 * The service routine for the urgent wake will dec
3661 * the semaphore itself for each item it consumes,
3662 * so add this one we just eat back.
3664 qemu_sem_post(&s->rate_limit_sem);
3665 urgent = true;
3667 trace_migration_rate_limit_post(urgent);
3669 return urgent;
3673 * Master migration thread on the source VM.
3674 * It drives the migration and pumps the data down the outgoing channel.
3676 static void *migration_thread(void *opaque)
3678 MigrationState *s = opaque;
3679 int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
3680 MigThrError thr_error;
3681 bool urgent = false;
3683 rcu_register_thread();
3685 object_ref(OBJECT(s));
3686 update_iteration_initial_status(s);
3688 qemu_savevm_state_header(s->to_dst_file);
3691 * If we opened the return path, we need to make sure dst has it
3692 * opened as well.
3694 if (s->rp_state.from_dst_file) {
3695 /* Now tell the dest that it should open its end so it can reply */
3696 qemu_savevm_send_open_return_path(s->to_dst_file);
3698 /* And do a ping that will make stuff easier to debug */
3699 qemu_savevm_send_ping(s->to_dst_file, 1);
3702 if (migrate_postcopy()) {
3704 * Tell the destination that we *might* want to do postcopy later;
3705 * if the other end can't do postcopy it should fail now, nice and
3706 * early.
3708 qemu_savevm_send_postcopy_advise(s->to_dst_file);
3711 if (migrate_colo_enabled()) {
3712 /* Notify migration destination that we enable COLO */
3713 qemu_savevm_send_colo_enable(s->to_dst_file);
3716 qemu_savevm_state_setup(s->to_dst_file);
3718 if (qemu_savevm_state_guest_unplug_pending()) {
3719 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
3720 MIGRATION_STATUS_WAIT_UNPLUG);
3722 while (s->state == MIGRATION_STATUS_WAIT_UNPLUG &&
3723 qemu_savevm_state_guest_unplug_pending()) {
3724 qemu_sem_timedwait(&s->wait_unplug_sem, 250);
3727 migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG,
3728 MIGRATION_STATUS_ACTIVE);
3731 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
3732 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
3733 MIGRATION_STATUS_ACTIVE);
3735 trace_migration_thread_setup_complete();
3737 while (migration_is_active(s)) {
3738 if (urgent || !qemu_file_rate_limit(s->to_dst_file)) {
3739 MigIterateState iter_state = migration_iteration_run(s);
3740 if (iter_state == MIG_ITERATE_SKIP) {
3741 continue;
3742 } else if (iter_state == MIG_ITERATE_BREAK) {
3743 break;
3748 * Try to detect any kind of failures, and see whether we
3749 * should stop the migration now.
3751 thr_error = migration_detect_error(s);
3752 if (thr_error == MIG_THR_ERR_FATAL) {
3753 /* Stop migration */
3754 break;
3755 } else if (thr_error == MIG_THR_ERR_RECOVERED) {
3757 * Just recovered from a e.g. network failure, reset all
3758 * the local variables. This is important to avoid
3759 * breaking transferred_bytes and bandwidth calculation
3761 update_iteration_initial_status(s);
3764 urgent = migration_rate_limit();
3767 trace_migration_thread_after_loop();
3768 migration_iteration_finish(s);
3769 object_unref(OBJECT(s));
3770 rcu_unregister_thread();
3771 return NULL;
3774 static void bg_migration_vm_start_bh(void *opaque)
3776 MigrationState *s = opaque;
3778 qemu_bh_delete(s->vm_start_bh);
3779 s->vm_start_bh = NULL;
3781 vm_start();
3782 s->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - s->downtime_start;
3786 * Background snapshot thread, based on live migration code.
3787 * This is an alternative implementation of live migration mechanism
3788 * introduced specifically to support background snapshots.
3790 * It takes advantage of userfault_fd write protection mechanism introduced
3791 * in v5.7 kernel. Compared to existing dirty page logging migration much
3792 * lesser stream traffic is produced resulting in smaller snapshot images,
3793 * simply cause of no page duplicates can get into the stream.
3795 * Another key point is that generated vmstate stream reflects machine state
3796 * 'frozen' at the beginning of snapshot creation compared to dirty page logging
3797 * mechanism, which effectively results in that saved snapshot is the state of VM
3798 * at the end of the process.
3800 static void *bg_migration_thread(void *opaque)
3802 MigrationState *s = opaque;
3803 int64_t setup_start;
3804 MigThrError thr_error;
3805 QEMUFile *fb;
3806 bool early_fail = true;
3808 rcu_register_thread();
3809 object_ref(OBJECT(s));
3811 qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX);
3813 setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
3815 * We want to save vmstate for the moment when migration has been
3816 * initiated but also we want to save RAM content while VM is running.
3817 * The RAM content should appear first in the vmstate. So, we first
3818 * stash the non-RAM part of the vmstate to the temporary buffer,
3819 * then write RAM part of the vmstate to the migration stream
3820 * with vCPUs running and, finally, write stashed non-RAM part of
3821 * the vmstate from the buffer to the migration stream.
3823 s->bioc = qio_channel_buffer_new(512 * 1024);
3824 qio_channel_set_name(QIO_CHANNEL(s->bioc), "vmstate-buffer");
3825 fb = qemu_fopen_channel_output(QIO_CHANNEL(s->bioc));
3826 object_unref(OBJECT(s->bioc));
3828 update_iteration_initial_status(s);
3831 * Prepare for tracking memory writes with UFFD-WP - populate
3832 * RAM pages before protecting.
3834 #ifdef __linux__
3835 ram_write_tracking_prepare();
3836 #endif
3838 qemu_savevm_state_header(s->to_dst_file);
3839 qemu_savevm_state_setup(s->to_dst_file);
3841 if (qemu_savevm_state_guest_unplug_pending()) {
3842 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
3843 MIGRATION_STATUS_WAIT_UNPLUG);
3845 while (s->state == MIGRATION_STATUS_WAIT_UNPLUG &&
3846 qemu_savevm_state_guest_unplug_pending()) {
3847 qemu_sem_timedwait(&s->wait_unplug_sem, 250);
3850 migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG,
3851 MIGRATION_STATUS_ACTIVE);
3852 } else {
3853 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
3854 MIGRATION_STATUS_ACTIVE);
3856 s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
3858 trace_migration_thread_setup_complete();
3859 s->downtime_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
3861 qemu_mutex_lock_iothread();
3864 * If VM is currently in suspended state, then, to make a valid runstate
3865 * transition in vm_stop_force_state() we need to wakeup it up.
3867 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, NULL);
3868 s->vm_was_running = runstate_is_running();
3870 if (global_state_store()) {
3871 goto fail;
3873 /* Forcibly stop VM before saving state of vCPUs and devices */
3874 if (vm_stop_force_state(RUN_STATE_PAUSED)) {
3875 goto fail;
3878 * Put vCPUs in sync with shadow context structures, then
3879 * save their state to channel-buffer along with devices.
3881 cpu_synchronize_all_states();
3882 if (qemu_savevm_state_complete_precopy_non_iterable(fb, false, false)) {
3883 goto fail;
3886 * Since we are going to get non-iterable state data directly
3887 * from s->bioc->data, explicit flush is needed here.
3889 qemu_fflush(fb);
3891 /* Now initialize UFFD context and start tracking RAM writes */
3892 if (ram_write_tracking_start()) {
3893 goto fail;
3895 early_fail = false;
3898 * Start VM from BH handler to avoid write-fault lock here.
3899 * UFFD-WP protection for the whole RAM is already enabled so
3900 * calling VM state change notifiers from vm_start() would initiate
3901 * writes to virtio VQs memory which is in write-protected region.
3903 s->vm_start_bh = qemu_bh_new(bg_migration_vm_start_bh, s);
3904 qemu_bh_schedule(s->vm_start_bh);
3906 qemu_mutex_unlock_iothread();
3908 while (migration_is_active(s)) {
3909 MigIterateState iter_state = bg_migration_iteration_run(s);
3910 if (iter_state == MIG_ITERATE_SKIP) {
3911 continue;
3912 } else if (iter_state == MIG_ITERATE_BREAK) {
3913 break;
3917 * Try to detect any kind of failures, and see whether we
3918 * should stop the migration now.
3920 thr_error = migration_detect_error(s);
3921 if (thr_error == MIG_THR_ERR_FATAL) {
3922 /* Stop migration */
3923 break;
3926 migration_update_counters(s, qemu_clock_get_ms(QEMU_CLOCK_REALTIME));
3929 trace_migration_thread_after_loop();
3931 fail:
3932 if (early_fail) {
3933 migrate_set_state(&s->state, MIGRATION_STATUS_ACTIVE,
3934 MIGRATION_STATUS_FAILED);
3935 qemu_mutex_unlock_iothread();
3938 bg_migration_iteration_finish(s);
3940 qemu_fclose(fb);
3941 object_unref(OBJECT(s));
3942 rcu_unregister_thread();
3944 return NULL;
3947 void migrate_fd_connect(MigrationState *s, Error *error_in)
3949 Error *local_err = NULL;
3950 int64_t rate_limit;
3951 bool resume = s->state == MIGRATION_STATUS_POSTCOPY_PAUSED;
3953 s->expected_downtime = s->parameters.downtime_limit;
3954 if (resume) {
3955 assert(s->cleanup_bh);
3956 } else {
3957 assert(!s->cleanup_bh);
3958 s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup_bh, s);
3960 if (error_in) {
3961 migrate_fd_error(s, error_in);
3962 migrate_fd_cleanup(s);
3963 return;
3966 if (resume) {
3967 /* This is a resumed migration */
3968 rate_limit = s->parameters.max_postcopy_bandwidth /
3969 XFER_LIMIT_RATIO;
3970 } else {
3971 /* This is a fresh new migration */
3972 rate_limit = s->parameters.max_bandwidth / XFER_LIMIT_RATIO;
3974 /* Notify before starting migration thread */
3975 notifier_list_notify(&migration_state_notifiers, s);
3978 qemu_file_set_rate_limit(s->to_dst_file, rate_limit);
3979 qemu_file_set_blocking(s->to_dst_file, true);
3982 * Open the return path. For postcopy, it is used exclusively. For
3983 * precopy, only if user specified "return-path" capability would
3984 * QEMU uses the return path.
3986 if (migrate_postcopy_ram() || migrate_use_return_path()) {
3987 if (open_return_path_on_source(s, !resume)) {
3988 error_report("Unable to open return-path for postcopy");
3989 migrate_set_state(&s->state, s->state, MIGRATION_STATUS_FAILED);
3990 migrate_fd_cleanup(s);
3991 return;
3995 if (resume) {
3996 /* Wakeup the main migration thread to do the recovery */
3997 migrate_set_state(&s->state, MIGRATION_STATUS_POSTCOPY_PAUSED,
3998 MIGRATION_STATUS_POSTCOPY_RECOVER);
3999 qemu_sem_post(&s->postcopy_pause_sem);
4000 return;
4003 if (multifd_save_setup(&local_err) != 0) {
4004 error_report_err(local_err);
4005 migrate_set_state(&s->state, MIGRATION_STATUS_SETUP,
4006 MIGRATION_STATUS_FAILED);
4007 migrate_fd_cleanup(s);
4008 return;
4011 if (migrate_background_snapshot()) {
4012 qemu_thread_create(&s->thread, "bg_snapshot",
4013 bg_migration_thread, s, QEMU_THREAD_JOINABLE);
4014 } else {
4015 qemu_thread_create(&s->thread, "live_migration",
4016 migration_thread, s, QEMU_THREAD_JOINABLE);
4018 s->migration_thread_running = true;
4021 void migration_global_dump(Monitor *mon)
4023 MigrationState *ms = migrate_get_current();
4025 monitor_printf(mon, "globals:\n");
4026 monitor_printf(mon, "store-global-state: %s\n",
4027 ms->store_global_state ? "on" : "off");
4028 monitor_printf(mon, "only-migratable: %s\n",
4029 only_migratable ? "on" : "off");
4030 monitor_printf(mon, "send-configuration: %s\n",
4031 ms->send_configuration ? "on" : "off");
4032 monitor_printf(mon, "send-section-footer: %s\n",
4033 ms->send_section_footer ? "on" : "off");
4034 monitor_printf(mon, "decompress-error-check: %s\n",
4035 ms->decompress_error_check ? "on" : "off");
4036 monitor_printf(mon, "clear-bitmap-shift: %u\n",
4037 ms->clear_bitmap_shift);
4040 #define DEFINE_PROP_MIG_CAP(name, x) \
4041 DEFINE_PROP_BOOL(name, MigrationState, enabled_capabilities[x], false)
4043 static Property migration_properties[] = {
4044 DEFINE_PROP_BOOL("store-global-state", MigrationState,
4045 store_global_state, true),
4046 DEFINE_PROP_BOOL("send-configuration", MigrationState,
4047 send_configuration, true),
4048 DEFINE_PROP_BOOL("send-section-footer", MigrationState,
4049 send_section_footer, true),
4050 DEFINE_PROP_BOOL("decompress-error-check", MigrationState,
4051 decompress_error_check, true),
4052 DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState,
4053 clear_bitmap_shift, CLEAR_BITMAP_SHIFT_DEFAULT),
4055 /* Migration parameters */
4056 DEFINE_PROP_UINT8("x-compress-level", MigrationState,
4057 parameters.compress_level,
4058 DEFAULT_MIGRATE_COMPRESS_LEVEL),
4059 DEFINE_PROP_UINT8("x-compress-threads", MigrationState,
4060 parameters.compress_threads,
4061 DEFAULT_MIGRATE_COMPRESS_THREAD_COUNT),
4062 DEFINE_PROP_BOOL("x-compress-wait-thread", MigrationState,
4063 parameters.compress_wait_thread, true),
4064 DEFINE_PROP_UINT8("x-decompress-threads", MigrationState,
4065 parameters.decompress_threads,
4066 DEFAULT_MIGRATE_DECOMPRESS_THREAD_COUNT),
4067 DEFINE_PROP_UINT8("x-throttle-trigger-threshold", MigrationState,
4068 parameters.throttle_trigger_threshold,
4069 DEFAULT_MIGRATE_THROTTLE_TRIGGER_THRESHOLD),
4070 DEFINE_PROP_UINT8("x-cpu-throttle-initial", MigrationState,
4071 parameters.cpu_throttle_initial,
4072 DEFAULT_MIGRATE_CPU_THROTTLE_INITIAL),
4073 DEFINE_PROP_UINT8("x-cpu-throttle-increment", MigrationState,
4074 parameters.cpu_throttle_increment,
4075 DEFAULT_MIGRATE_CPU_THROTTLE_INCREMENT),
4076 DEFINE_PROP_BOOL("x-cpu-throttle-tailslow", MigrationState,
4077 parameters.cpu_throttle_tailslow, false),
4078 DEFINE_PROP_SIZE("x-max-bandwidth", MigrationState,
4079 parameters.max_bandwidth, MAX_THROTTLE),
4080 DEFINE_PROP_UINT64("x-downtime-limit", MigrationState,
4081 parameters.downtime_limit,
4082 DEFAULT_MIGRATE_SET_DOWNTIME),
4083 DEFINE_PROP_UINT32("x-checkpoint-delay", MigrationState,
4084 parameters.x_checkpoint_delay,
4085 DEFAU